ADN
(Advanced Digital Network) -- Usually refers to a 56Kbps leased-line.

Applet
A small Java program that can be embedded in an HTML page. Applets differ from full-fledged Java applications in that they are not allowed to access certain resources on the local computer, such as files and serial devices (modems, printers, etc.), and are prohibited from communicating with most other computers across a network. The current rule is that an applet can only make an Internet connection to the computer from which the applet was sent.

Archie
A tool (software) for finding files stored on anonymous FTP sites. You need to know the exact file name or a substring of it.

ARPANet
(Advanced Research Projects Agency Network) -- The precursor to the Internet. Developed in the late 60’s and early 70’s by the US Department of Defense as an experiment in wide-area-networking that would survive a nuclear war.

ASCII
(American Standard Code for Information Interchange) -- This is the de facto world-wide standard for the code numbers used by computers to represent all the upper and lower-case Latin letters, numbers, punctuation, etc. There are 128 standard ASCII codes each of which can be represented by a 7 digit binary number: 0000000 through 1111111.

Backbone
A high-speed line or series of connections that forms a major pathway within a network. The term is relative as a backbone in a small network will likely be much smaller than many non-backbone lines in a large network.

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.

Baud
In common usage the baud rate of a modem is how many bits it can send or receive per second. Technically, baud is the number of times per second that the carrier signal shifts value - for example a 1200 bit-per-second modem actually runs at 300 baud, but it moves 4 bits per baud (4 x 300 = 1200 bits per second).

BBS
(Bulletin Board System) -- A computerized meeting and announcement system that allows people to carry on discussions, upload and download files, and make announcements without the people being connected to the computer at the same time. There are many thousands (millions?) of BBS’s around the world, most are very small, running on a single IBM clone PC with 1 or 2 phone lines. Some are very large and the line between a BBS and a system like CompuServe gets crossed at some point, but it is not clearly drawn.

Binhex
(BINary HEXadecimal) -- A method for converting non-text files (non-ASCII) into ASCII. This is needed because Internet e-mail can only handle ASCII.

Bit
(Binary DigIT) -- A single digit number in base-2, in other words, either a 1 or a zero. The smallest unit of computerized data. Bandwidth is usually measured in bits-per-second.

BITNET
(Because It’s Time NETwork (or Because It’s There NETwork)) -- A network of educational sites separate from the Internet, but e-mail is freely exchanged between BITNET and the Internet. Listservs?, the most popular form of e-mail discussion groups, originated on BITNET. BITNET machines are usually mainframes running the VMS operating system, and the network is probably the only international network that is shrinking.

Bps
(Bits-Per-Second) -- A measurement of how fast data is moved from one place to another. A 28.8 modem can move 28,800 bits per second.

Browser
A Client program (software) that is used to look at various kinds of Internet resources.

BTW
(By The Way) -- A shorthand appended to a comment written in an online forum.

Byte
A set of Bits that represent a single character. Usually there are 8 Bits in a Byte, sometimes more, depending on how the measurement is being made.