Glossary of Computer Terms

Computer Terms Glossary

This page is meant to serve as a guide to the vast quantity of computer terms and acronyms in common use for the casual computer user. It is divided into two main sections, the first is dedicated to the basics and is meant more for beginners, while the second is meant instead to be used as a reference. In reality many of the terms in the second section are still quite common; the first section was deliberately kept as short as possible.

Terms in the second section may be looked up by either using the "find in page" function of your browser, or by appending "#term" (without the quotes and where term is the term of interest) to the "URL" or "go to" section of your browser, keeping in mind that case matters. The best method of searching for a term though is to use the Search Interface that will return not only the specific term sought but also other entries that reference it. Be aware that the terms referenced in the second part of this page will freely assume familiarity with the first part.

If you are instead actually trying to figure out what a particular filename extension means, you might instead try the filename extensions page.

If you want something added or see a problem with something already here (but keep in mind this guide is not meant to be overly technical) please send .


Starting up an OS is booting it. If the computer is already running, it is more often called rebooting.
A browser is a program used to browse the web. Some common browsers include Netscape, MSIE (Microsoft Internet Explorer), Safari, Lynx, Mosaic, Amaya, Arena, Chimera, Opera, Cyberdog, HotJava, etc.
A bug is a mistake in the design of something, especially software. A really severe bug can cause something to crash.


The Beginners' All-purpose Symbolic Instruction Code is a computer language developed by Kemeny & Kurtz in 1964. Although it is traditionally interpreted, compilers exist for many platforms. While the interpreted form is typically fairly slow, the compiled form is often quite fast, usually faster than Pascal. The biggest problem with BASIC is portability; versions for different machines are often completely unlike each other; Amiga BASIC at first glance looks more like Pascal, for example. Portability problems actually go beyond even the cross platform level; in fact, most machines have multiple versions of incompatible BASICs available for use. The most popular version of BASIC today is called Visual BASIC. Like all BASICs it has portability issues, but it has some of the advantages of an authoring system so it is relatively easy to use.
A measure of communications speed, used typically for modems indicating how many bits per second can be transmitted.
A bulletin board system is a computer that can be directly connected to via modem and provides various services like e-mail, chatting, newsgroups, and file downloading. BBSs have waned in popularity as more and more people are instead connecting to the Internet, but they are still used for product support and local area access. Most current BBSs provide some sort of gateway connection to the Internet.
Identical in intent to uucode, bcode is slightly more efficient and more portable across different computer types. It is the preferred method used by MIME.
A lightweight OS available for both PowerPC and x86 based machines. It is often referred to simply as "Be".
A beta version of something is not yet ready for prime time but still possibly useful to related developers and other interested parties. Expect beta software to crash more than properly released software does. Traditionally beta versions (of commercial software) are distributed only to selected testers who are often then given a discount on the proper version after its release in exchange for their testing work. Beta versions of non-commercial software are more often freely available to anyone who has an interest.
There are two meanings for binary in common computer usage. The first is the name of the number system in which there are only zeros and ones. This is important to computers because all computer data is ultimately a series of zeros and ones, and thus can be represented by binary numbers. The second is an offshoot of the first; data that is not meant to be intepreted through a common character set (like ASCII) is typically referred to as binary data. Pure binary data is typically eight bit data, and transferring a binary file through ASCII channels without prior modification will result in corruption and loss of data. Binary data can be turned into ASCII data via uucoding or bcoding.
A bit can either be on or off; one or zero. All computer data can ultimately be reduced to a series of bits. The term is also used as a (very rough) measure of sound quality, color quality, and even procesor capability by considering the fact that series of bits can represent binary numbers. For example (without getting too technical), an eight bit image can contain at most 256 distinct colors while a sixteen bit image can contain at most 65,536 distinct colors.
A bitmap is a simplistic representation of an image on a computer, simply indicating whether or not pixels are on or off, and sometimes indicating their color. Often fonts are represented as bitmaps. The term "pixmap" is sometimes used similarly; typically when a distinction is made, pixmap refers to color images and bitmap refers to monochrome images.
Short for web log, a blog (or weblog, or less commonly, 'blog) is a web site containing periodic (usually frequent) posts. Blogs are usually syndicated via either some type of RSS or Atom and often supports TrackBacks. It is not uncommon for blogs to function much like newspaper columns. A blogger is someone who writes for and maintains a blog.
Boolean algebra is the mathematics of base two numbers. Since base two numbers have only two values, zero and one, there is a good analogy between base two numbers and the logical values "true" & "false". In common usage, booleans are therefore considered to be simple logical values like true & false and the operations that relate them, most typically "and", "or" and "not". Since everyone has a basic understanding of the concepts of true & false and basic conjunctions, everyone also has a basic understanding of boolean concepts -- they just may not realize it.
A byte is a grouping of bits. It is typically eight bits, but there are those who use non-standard byte sizes. Bytes are usually measured in large groups, and the term "kilobyte" (often abbreviated as K) means one-thousand twenty-four (1024) bytes; the term "megabyte" (often abbreviated as M) means one-thousand twenty-four (1024) K; the term gigabyte (often abbreviated as G) means one-thousand twenty-four (1024) M; and the term "terabyte" (often abbreviated as T) means one-thousand twenty-four (1024) G. Memory is typically measured in kilobytes or megabytes, and disk space is typically measured in megabytes or gigabytes. Note that the multipliers here are 1024 instead of the more common 1000 as would be used in the metric system. This is to make it easier to work with the binary number system. Note also that some hardware manufacturers will use the smaller 1000 multiplier on M & G quantities to make their disk drives seem larger than they really are; buyer beware.
Sometimes computer languages that are said to be either interpreted or compiled are in fact neither and are more accurately said to be somewhere in between. Such languages are compiled into bytecode which is then interpreted on the target system. Bytecode tends to be binary but will work on any machine with the appropriate runtime environment (or virtual machine) for it.