Internet Glossary

This glossary contains a range of definitions that attempt to cover a broad spectrum of Internet and Telecommunications technologies, applications, devices, and concepts. However, this is not a comprehensive list. If you come across an unfamiliar acronym or term not listed here, please consider searching the Tech Terms website or utilizing your preferred search engine. 

Here is a brief history of the internet for more context.

ADSL (Asymmetric Digital Subscriber Line) 

A type of Digital Subscriber Line (DSL) that has different upload and download speeds. 

See https://en.wikipedia.org/wiki/Digital_subscriber_line 
See https://techterms.com/definition/adsl 

Address Bar 

The field at the top of a web browser displaying the URL of the webpage that is being accessed. A known web address can be entered into this field in order to access the associate webpage. 

See: https://techterms.com/definition/address_bar  

Application 

The term application refers to a type of software program that runs on a computer or mobile device including e-mail, web browsers, and games. Each program has a specific “application” or use. 

See: https://techterms.com/definition/application  

Attachment 

A file, such as a document, image, video, or any other file type, that is sent using email or another web-based messaging application. 

See: https://techterms.com/definition/attachment  

Backbone 

A “backbone” refers to the main lines of a network that link several local area networks (LANs) together, creating a wide area network (WAN). In regards to the Internet, the backbone is the large scale cable or fiber infrastructure that connects major network service providers (NSPs). 

See: https://techterms.com/definition/backbone   

Bandwidth 

There are two definitions of bandwidth.  

The first, is a description of the maximum data transfer rate of a given network or Internet connection. This is not the speed at which say a given bit of data travels, but rather a measure of how much data can flow through the given connection at one time. This definition is typically measured in multiples of bits per second (bps), e.g., Kilobits per second (Kbps = 1,000 bps), Megabits per second (Mbps = 1,000 Kbps) or Gigabits per second (Gbps = 1,000 Mbps). 

The second, refers to a range of frequencies used to transmit an electromagnetic signal that are typically measured in hertz. 

See: https://techterms.com/definition/bandwidth  

Broadband 

Refers to several technologies used to connect to the Internet. The connection is “always on” meaning that data can be sent to and from the user at a bandwidth greater than that provided by a dial-up modem. Broadband is often referred to as “high-speed internet”. In addition, the current FCC definition of broadband is a connection speed of at least 25 Mbps download and 3 Mbps upload. 

See: https://techterms.com/definition/broadband  

See: https://www.fcc.gov/general/types-broadband-connections  

Bit 

The term “bit” is short for “binary digit,” and it represents the smallest unit of measurement for computer data. A bit contains a single binary value of either 1 or 0. 
See: https://techterms.com/definition/bit  

Byte 

A byte is a data measurement unit that contains 8 bits, or a string of eight ones and zeros. Currently, bytes and multiples of bytes are the fundamental units of measurement for data storage capacity, e.g., Kilobytes (KB = 1,000 bytes), Megabytes (MB = 1,000 KB), or Gigabytes (GB = 1,000 MB). 

See: https://techterms.com/definition/byte 

Cloud Computing 

This term refers to web-based services and applications, like online data storage and backup systems, and derives from the use of the term “cloud” as a metaphor for the network structure of the Internet.  

See: https://techterms.com/definition/cloud_computing  

See: https://techterms.com/definition/cloud  

CO (Central Office) 

Central Office, a hardened communications/data facility where core transport networks interface with a distribution network that serves individual residences, multi-dwelling units, campuses and businesses.  

Coaxial Cable 

Coaxial “coax” cable is a common type of cable used for transmitting data over long distances. Signal is transmitted by a solid copper wire with multiple layers of insulation to prevent signal interference. While much existing coax cable installed for commercial use is suitable for both HDTV and cable internet connection, some coax cable meant for residential purposes may not provide enough bandwidth capacity for a cable internet connection. 

See: https://techterms.com/definition/coaxial_cable  

Cookie 

The term “cookie” refers to small pieces of data that websites generate to track the preferences of their users. Many websites now inform you of their use of cookies when you visit and actively require that you consent to their use of the preference data they gather and store on your web browser. 

See: https://techterms.com/definition/cookie  

Data 

This information, usually composed of “bits” of information may be in the form of text documents, images, audio clips, software programs, or other types of data. 

See https://techterms.com/definition/data  

Data Transfer Rate 

This is a measurement of how fast data is transferred from one location to another, typically measured in multiples of bits per second (bps). 

See: https://techterms.com/definition/datatransferrate  

Dial-up 

This refers to an internet connection that is established by using a modem and existing telephone lines to connect to an ISP. Dial-up connections offer very low speeds (56 Kbps) in comparison to newer types of internet connections such as DSL and cable modems. 

See https://techterms.com/definition/dialup  

Digital Footprint 

The trail of data that is created as you use the Internet. It can be generated passively as you visit a website and the web server logs your IP address, or actively as you use web-based applications such as email. 

See: https://techterms.com/definition/digital_footprint  

DNS (Domain Name System) 

Domain name system translates domain names, or the names of websites (think Google or Facebook), into IP addresses, so that you can access websites by their easy to remember name as opposed to an IP address. 

See: https://techterms.com/definition/dns  

DOCSIS 

Data Over Cable Service Interface Specification (DOCSIS) is the interface for cable modems to provide Internet access over cable distribution systems. DOCSIS 3.1 is the latest update to the DOCSIS specification in use today. DOCSIS 4.0 is currently in process through the Society of Cable Telecommunications Engineers and CableLabs. 

See: https://www.cablelabs.com/technologies/docsis-3-1 

DS (Down-Stream)  

A common unit of Internet connection speed that defines the speed available from the network service provider (NSP) to the user.  

See: https://en.wikipedia.org/wiki/Downstream_%28networking%29  

DSL (Digital Subscriber Line) 

A technology that allows for Internet connection over standard telephone lines. There are two formats for DSL, symmetric (SDSL) and asymmetric (ADSL), meaning that upload and download speeds are either the same or, since users typically download more than they upload, split unevenly to allow for faster download speeds. 

See: https://en.wikipedia.org/wiki/Digital_subscriber_line 

See: https://techterms.com/definition/dsl  

EDFA (Erbium Doped Fiber Amplifier) 

Erbium Doped Fiber Amplifier, a fiber optic amplifier that is often used in Fiber-to-the-Home optical networks to amplify wavelengths between 1530nm (C-band) and 1625nm (L-band). 

See: https://www.webopedia.com/definitions/edfa/  

Electromagnetic Signal 

Electromagnetic radiation in the form of waves of varying frequency and energy, including radio waves, microwaves, and visible light, is the method by which data is transferred. All electromagnetic waves travel at the speed of light and analog signals (physical differences in frequency or amplitude) can be translated into digital bits of data. To be clear, the energy of EM waves used to transmit data via the Internet is very low even in comparison to visible light. 

See: https://en.wikipedia.org/wiki/Electromagnetic_radiation#Electromagnetic_spectrum  

Encryption 

Encryption is a method used to protect information by converting data to an unrecognizable form. Encrypted files may require a password or a “key” in order to access the secure information. The modern standard for encryption is 256-bit encryption, meaning that there are 2256 possible combinations for the password or “key,” ensuring the safety of sensitive data by making unauthorized access almost impossible. 

See: https://techterms.com/definition/encryption  

See: https://www.techopedia.com/definition/29703/256-bit-encryption  

Ethernet 

The standard type of cable used to connect multiple computers and other hardware devices like a routermodem, or switch on a local network (LAN). There are multiple standards that range from a 10 Mbps connection (10BASE-T) to a Gigabit connection (1000BASE-T), and it is important to remember that network speed falls to the lowest common denominator. This means that even with a Gigabit connection from your ISP a 10BASE-T cable will limit your network speed to 10 Mbps. 

See: https://techterms.com/definition/ethernet  

Fiber Optic Cable (“fiber”) 

Fiber is a type of data transmission cable that uses glass or plastic filaments to carry rapid pulses of light. Fiber provides the fastest data transfer rate of any data transmission medium, and they are used for a large portion of the Internet backbone. ISPs in some areas now offer “fiber Internet” services that allow for connections speeds of 1 Gbps or greater.  

See: https://techterms.com/definition/fiber_optic_cable  

Fixed Wireless Internet 

This is the use of wireless data transfers over radio, microwave, or other wireless link to connect two fixed locations. In practice, this means that locations can access the Internet without having to install new copper or fiber data transmission cables. 

See: https://en.wikipedia.org/wiki/Fixed_wireless  

Frequency 

Frequency is a measurement of the number of times something occurs in a given time period. In this context frequency may be used to measure the rate of electromagnetic waves used to transmit data. Also, frequency is often used to measure the processing speed of computers, i.e., how many cycles or operations per second a processor can complete. 

See: https://techterms.com/definition/frequency 

FTTH (Fiber-to-the-Home) 

This refers to the installation and use of fiber optic cable that is routed directly from a central ISP to the home, residence, or premises. 

See: https://searchnetworking.techtarget.com/definition/fiber-to-the-home    

FTTH – WDM (Wavelength Division Multiplexing) 

In a fiber optic distribution system, a single light wavelength is assigned to a single user or to fewer than 20 users sharing the same wavelength. Multiple wavelengths are combined in a single fiber strand. 

See: https://foa.org/tech/dwdm.htm  

FTTH – RFoG (Radio Frequency over Glass) 

A transmission method that can increase network capacity by expanding the available wavelengths used for data transmission over a PON

See: https://en.wikipedia.org/wiki/Radio_frequency_over_glass  

See: https://www.foa.org/tech/ref/appln/FTTH-PON.html  

FTTH – GPON (Gigabit-capable Passive Optical Network) 

In a fiber optic distribution system, a single light wavelength is assigned to less than 128 users sharing the same wavelength carried through a single fiber strand. This allows the network to have 1Gbps bandwidth. 

See: https://www.foa.org/tech/ref/appln/FTTH-PON.html  

HDT (Host Digital Terminal) 

Host Digital Terminal, the network device typically located in a Central Office or communications/data facility that connects to a Remote Digital Terminal to serve neighborhoods. 

HHP (Households Passed) 

Households Passed, a unit measuring the number of residences that can be connected to and served by a node. 

See: https://www.lawinsider.com/dictionary/homes-passed  

High Orbit Satellite Internet 

High orbit typically refers to satellites that orbit at or above a “geostationary orbit” of about 22,000 miles above the Earth’s equator. To an observer on the ground, these satellites appear stationary as their orbit is nearly circular and equivalent to the speed of the Earth’s rotation. These satellites experience high latency due to the round trip distance data must travel. Even with perfect conditions, at the speed of light it can take radio waves 250 milliseconds (MS) to travel to the satellite and back to the end user. When normal network delays are factored in it can take between .5 and 1.5 seconds for the data to make the round trip. This is often twice as great as the delay with dial-up service and much greater than the 15-40ms latency for high-speed cableDSL, or fiber Internet service.  

See: https://en.wikipedia.org/wiki/Satellite_Internet_access#Geostationary_orbits  

Hotspot 

A hotspot refers to a location that has a Wi-Fi network connection outside of say your home or office. In some areas there are public spaces, e.g., libraries, cafes, airports, businesses, that offer Wi-Fi hotspots. In addition, some cellular carriers offer dedicated mobile devices or plans that allow your cell phone to act as a hotspot. 

See: https://www.businessinsider.com/what-is-a-hotspot  

HTTP (hypertext transfer protocol) 

This is a part of the Internet protocol that is used to transfer webpage data. When you access a website from your computer, laptop, or mobile device, your Internet browser sends a request to the server that hosts the website and, depending on the response, the server will send the webpage and related files back to your browser. 

See: https://techterms.com/definition/http  

HTTPS (hypertext transfer protocol secure) 

This is functionally equivalent to HTTP, but it uses a secure socket layer (SSL) to encrypt the data that is being transferred between your device and the server that hosts a webpage.  

See: https://techterms.com/definition/https  

Internet 

The Internet is the term for the global wide area network (WAN) that connects computer systems, including multiple high-bandwidth data lines (Backbone) and hubs that distribute data to servers and ISPs

See: https://techterms.com/definition/internet  

IoT (Internet of Things) 

Internet of Things, a new set of tech solutions that often includes appliances, sensor probes, and a variety of “smart” devices that are usually connected via the Internet. 

See: https://en.wikipedia.org/wiki/Internet_of_thing  

IP (Internet Protocol) Address 

A unique identifier for a device connected to the Internet or a local network that allows the system to be recognized by other devices. 

See: https://techterms.com/definition/ip_address  

ISP (Internet Service Provider) 

An organization that provides access to the internet. ISPs offer a variety of Internet connection types such as dial-upDSLcable, and, increasingly, fiber. ISPs often act as Internet hubs due to their high volume of traffic and direct connection to portions of the Internet backbone. 

See: https://techterms.com/definition/isp 

ITU (International Telecommunication Union) 

International Telecommunication Union, an international telecommunications standards body, responsible for publishing specifications and interoperability standardization. 

See: https://www.itu.int/en/Pages/default.aspx  

LAN (local area network) 

This is a type of network that connects devices in a specific location, e.g., educational institution, business, or home. A LAN connection can allow connected devices to communicate and access shared files and data. 

See: https://techterms.com/definition/lan  

Last Mile 

The phrase “last mile” is used widely across industries and in this context refers to the final leg of a network that delivers service to the retail customer or end-user. When providing Internet access, proper planning for the last mile is crucial in preventing “bottlenecks” or slow service speed due to inadequate bandwidth. 

See: https://en.wikipedia.org/wiki/Last_mile  

Low Orbit Satellite Internet 

This type of satellite Internet access has shorter delays than high orbit satellites, but it requires a greater number of devices to ensure adequate and continuous service. Additionally, it may also require more sophisticated ground antennae to track the movement of satellites and maintain connection. For certain rural areas, this type of connection may be the most cost-effective, if existing or planned satellite arrays will provide reliable coverage, because it would not require new cable or fiber to be installed. 

See: https://en.wikipedia.org/wiki/Satellite_Internet_access#Medium_and_Low_Earth_Orbits  

Mbps (megabits per second) 

A megabit is equal to one million (1,000,000) bits, and megabits per second is the measurement most often used to indicate the data transfer rates of high bandwidth connections like cable modems. 

See: https://techterms.com/definition/mbps  

Mobile Wireless Internet 

This is a type of service that is available through cellular networks. It may require special hardware such as a network card and antennae that will allow devices other than smart phones to connect to a cellular network. Often this type of connection offers only limited bandwidth. 

See: https://www.fcc.gov/general/types-broadband-connections  

Modem 

This is an abbreviation for “Modulator-Demodulator,” a piece of hardware that allows a computer, router, or switch to connect to the internet by converting analog electrical signal from a telephone line or cable connection to a digital signal that a computer can recognize. 

See: https://techterms.com/definition/modem   

NSP (network service provider) 

A business providing access to the Internet backbone. Some ISPs are also NSPs, but in many cases, NSPs build and maintain primary Internet infrastructure, such as fiber optic lines between hubs, and provide Internet access to ISPs that in turn provide access to end-users. 

See: https://techterms.com/definition/nsp  

ONT (Optical Network Terminal) 

Optical Network Terminal, the network device located at the business or residence that connects the business/residence to an optical distribution network. 

ONU (Optical Network Unit) 

Optical Network Unit, the network device located at a communications/data facility or Remote Host Terminal (fiber optic node) to interface via the fiber optic distribution network with Optical Network Terminals and connect to transport network(s). 

Packet 

Packets are used to break up larger files into small amounts of data that contain information about the source, destination, and a payload of the data being transferred. This helps ensure that data is transferred reliably and efficiently. 

See: https://techterms.com/definition/packet  

PON (passive optical network) 

A type of network that transmits data over fiber optic lines and uses unpowered splitters to route data from a central location to multiple destinations. This is a cost-effective way for an ISP to provide access to end-users because the system can split a single high-bandwidth line to communicate with many smaller, separate lines that require less infrastructure than direct lines to multiple locations. 

See: https://techterms.com/definition/pon  

RDT (Remote Digital Terminal) 

Remote Digital Terminal, the network device typically located in a neighborhood and interfaces to a Host Digital Terminal at a nearby communications/data facility. 

Router 

A hardware device that routes data from a LAN to another network connection and allows authorized devices to connect to other computer systems and the Internet

See: https://techterms.com/definition/router  

SaaS (Software-as-a-Service) 

This refers to web-based software that is deployed via the Internet as opposed to being installed on a computer. These applications run on a web browser and SaaS is seen as a type of cloud computing

See: https://techterms.com/definition/saas  

SCTE 

The Society of Cable Telecommunications Engineers (SCTE) is a not for profit, member organization that engages in applied science at the leading edge of the telecommunications industry. 

See: https://www.scte.org/about/  

Signal Range/Reach 

The distance between a service node and the farthest user. It may be represented in cable miles or a propagation distance from a wireless station. It is the distance over which bandwidth and throughput can be maintained. 

SSL (secure sockets layer) 

This is a protocol developed to encrypt data and send it securely over the Internet. It is used primarily for websites that require sensitive personal information like your name, address, or credit card numbers, and in instances where you log in to a user account. 

See: https://techterms.com/definition/ssl  

Starlink 

Starlink is a low-orbit satellite-based ISP that aims to utilize a constellation of small satellites to offer broadband or greater level Internet access. It is a division of Elon Musk’s SpaceX and the service is currently in beta testing with users expected to experience data speeds ranging between 50-150Mbps. 

See: https://www.starlink.com/  

Switch 

A hardware device with multiple Ethernet ports that is used to network multiple devices together including computers, modems, and other switches.  

See: https://techterms.com/definition/switch  

Throughput  

The measures of the rate at which data is transmitted through the internet to a destination successfully. It is a practical measure of data delivery rather than the theoretical capacity of a network.  

See: https://www.comparitech.com/net-admin/throughput-vs-bandwidth/#What_is_Throughput 

URL (Uniform Resource Locator) 

The web address of a specific file or webpage on the Internet. A URL works in tandem with DNS, hypertext transfer protocol (HTTP), and IP addresses to find and deliver data accessible on the Internet. 

See: https://techterms.com/definition/url  

US (Up-Stream) 

A common unit of Internet connection speed that defines the speed available from the user to the network service provider (NSP). 

See: https://en.wikipedia.org/wiki/Upstream_%28networking%29  

WAN (wide area network) 

A WAN is similar to a LAN but on a much larger scale not limited by a single location. For instance, one could describe the Internet – as is done above – as a global WAN. WANs can cover long distances via telephone lines, fiber optic cables, or satellite links, and they can also be composed of interconnected LANs. 

See: https://techterms.com/definition/wan  

Wireless 

There are multiple types of “wireless” technologies including Wi-Fi and Bluetooth. Wi-Fi refers to wireless networking technologies wherein a Wi-Fi enabled device transmits data to a wireless router that is usually connected to another network device such as a DSL or cable modem that provides access to the Internet. Bluetooth technology is more often used for smaller wireless devices to communicate with one another such as a wireless keyboard or mouse, speakers, and headsets. 

See: https://techterms.com/definition/wireless  

Wireless Internet 

This is a type of Internet connection that is offered by wireless Internet service providers (WISPs) utilizing radio waves or satellite signal instead of a direct, physical telephone, cable, or fiber optic line to a home or business. In addition, Wi-Fi hotspots and wireless LANs can also offer wireless Internet access. 

See: https://www.techopedia.com/definition/30142/wireless-internet  

See: https://www.webopedia.com/definitions/wireless-internet/  

Wireless Modem 

A hardware device that allows computers to connect to a wireless local area network (WLAN) without a direct connection such as an Ethernet cable. Depending on the device, connection options can include cellular, satellite, and Wi-Fi. 

See: https://www.techopedia.com/definition/3019/wireless-modem  

Wireline 

A term used to describe types of transmission technology that use physical cables or wiring (telephone, coax, fiber) to transmit data and provide Internet access. 

See: https://www.multapplied.net/wireline-vs-wireless-is-there-really-a-perfect-access-technology/  

3G 

This refers to the third generation of cellular communications technologies that meet an international standard for peak cellular data transfer rates, e.g., at least 2Mbps.  

See: https://techterms.com/definition/3g  

4G 

This is the fourth generation of cellular communications technologies that meet international requirements for peak data transfer rates of at least 100Mbps. 

See: https://techterms.com/definition/4g  

5G 

The fifth generation of cellular communications technologies that succeeds all 4G standards including LTE. 5G technology has a theoretical maximum data transfer rate of 20Gbps (200 times faster than standard 4G) and uses a wider range of frequencies that can be optimized for different environments. For example, low frequencies that travel father are better suited to rural areas with greater distances between cell towers. 

See: https://techterms.com/definition/5g