T

THUMBNAIL
Thumbnails are reduced-size versions of pictures, used to help in recognizing and organizing them, serving the same role for images as a normal text index does for words.

Tag
In web terms: Notifications or commands written into a web document. (See HTML Tags)

TCP (Transmission Control Protocol)
See TCP/IP.

TCP/IP (Transmission Control Protocol / Internet Protocol)
A collection of Internet communication protocols between two computers. The TCP protocol is responsible for an error free connection between two computers, while the IP protocol is responsible for the data packets sent over the network.
Learn more about TCP/IP in our TCP/IP tutorial

TCP/IP Address
See IP Address.

TCP/IP Packet
A "packet" of data sent over a TCP/IP network. (data sent over the Internet is broken down into small "packets" from 40 to 32000 bytes long).

Trojan Horse
Computer program hidden in another computer program with the purpose of destroying software or collecting information about the use of the computer.


T1

Dedicated telecommunications line providing 1.5 Mbps of bandwidth. Consists of 24 individual channels 64 Kbps each, that can be configured for voice or data transmission. T1 lines can be leased by businesses that required a dedicated Net connection of with higher reliability than a DSL and faster than an ISDN line but are still quite expensive.

T3

Dedicated telecommunications line providing 44 Mbps of bandwidth. T3 lines are often used by ISPs to connect to the Internet backbone.

Tcl

Tool command language. Simple scripting language and library often used for GUI, string-manipulation, testing, and integration of multiple components.

TCP

(Transmission Control Protocol) is the most important of the network protocols used in the Internet.

TCP/IP

(Transmission Control Protocol/Internet Protocol). This protocol suite is the de facto standard for the today's Internet. TCP is a higher level protocol that runs on top of the IP protocol.

Telnet

Character-based protocol for connecting with remote systems. Still popular among hosts, but it is being replaced by much more secure SSH access.

Terabyte (TB)

1024 gigabytes

TIA

Telecommunications Industry Association. Another telecommunications standards organization.

TLD

Top Level Domain. The domain name elements at the right, such as .com, .org or .gov. Recently, new TLDs like .pro or .museum were added to supplement older TLDs. ccTLDs (country code TLDs), like .uk or .fr are used per-country.

Traceroute

A computer program that lists network hosts visited by a packed on the way to its destination. Very useful for network debugging.

Traffic

Data packets being transmitted over a network.

Twisted Pair

A pair of wires twisted one around the other. Very common in the networking applications.