Bandwidth
How much stuff you can send through a connection. Usually measured in bits-per-second. A full page of English text is about 16,000 bits. A fast modem can move about 15,000 bits in one second. Full-motion full-screen video would require roughly 10,000,000 bits-per-second, depending on compression.
Client
A software program that is used to contact and obtain data from a Server software program on another computer, often across a great distance. Each Client program is designed to work with one or more specific kinds of Server programs, and each Server requires a specific kind of Client. A Web Browser is a specific kind of Client.
Ethernet
A very common method of networking computers in a LAN. Ethernet will handle about 10,000,000 bits-per-second and can be used with almost any kind of computer.
Fire Wall
A combination of hardware and software that separates a LAN (Local Area Network) into two or more parts for security purposes.
Gateway
The simple explanation of gateway is to describe any mechanism for providing access to another system, e.g. AOL might be called a gateway to the Internet. The technical meaning is a hardware or software set-up that translates between two dissimilar protocols, for example Prodigy has a gateway that translates between its internal, proprietary e-mail format and Internet e-mail format.
LAN
(Local Area Network) -- A computer network limited to the immediate area, usually the same building or floor of a building.
Network
Any time you connect 2 or more computers together so that they can share resources, you have a computer network. Connect 2 or more networks together and you have an Internet.
Server
A computer, or a software package, that provides a specific kind of service to client software running on other computers. The term can refer to a particular piece of software, such as a WWW server, or to the machine on which the software is running, e.g.Our mail server is down today, thatŐs why our e-mail isnŐt getting out. A single server machine could have several different server software packages running on it, thus providing many different servers to clients on the network.
T-1
A leased-line connection capable of carrying data at 1,544,000 bits-per-second. A T-1 line could move a megabyte in less than 10 seconds. T-1 is the fastest speed commonly used to connect networks to the Internet.
T-3
A leased-line connection capable of carrying data at 44,736,000 bits-per-second. This is more than enough to do full-screen, full-motion video.
http://www.matisse.net/files/glossary.html