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 .


A database is a collection of data, typically organized to make common retrievals easy and efficient. Some common database programs include Oracle, Sybase, Postgres, Informix, Filemaker, Adabas, etc.
A desktop system is a computer designed to sit in one position on a desk somewhere and not move around. Most general purpose computers are desktop systems. Calling a system a desktop implies nothing about its platform. The fastest desktop system at any given time is typically either an Alpha or PowerPC based system, but the SPARC and PA-RISC based systems are also often in the running. Industrial strength desktops are typically called workstations.
Also called "folder", a directory is a collection of files typically created for organizational purposes. Note that a directory is itself a file, so a directory can generally contain other directories. It differs in this way from a partition.
A disk is a physical object used for storing data. It will not forget its data when it loses power. It is always used in conjunction with a disk drive. Some disks can be removed from their drives, some cannot. Generally it is possible to write new information to a disk in addition to reading data from it, but this is not always the case.
A device for storing and/or retrieving data. Some drives (such as disk drives, zip drives, and tape drives) are typically capable of having new data written to them, but some others (like CD-ROMs or DVD-ROMs) are not. Some drives have random access (like disk drives, zip drives, CD-ROMs, and DVD-ROMs), while others only have sequential access (like tape drives).


desktop publisher
A program for creating newspapers, magazines, books, etc. Some common desktop publishing programs include FrameMaker, PageMaker, InDesign, and GeoPublish.
Dynamic HTML is simply the combined use of both CSS and JavaScript together in the same document; a more extreme form is called AJaX. Note that DHTML is quite different from the similarly named DTML.
A protocol used for looking up definitions across a network (in particular the Internet).
digital camera
A digital camera looks and behaves like a regular camera, except instead of using film, it stores the image it sees in memory as a file for later transfer to a computer. Many digital cameras offer additional storage besides their own internal memory; a few sport some sort of disk but the majority utilize some sort of flash card. Digital cameras currently lack the resolution and color palette of real cameras, but are usually much more convenient for computer applications. Another related device is called a scanner.
A physical component used to add RAM to a computer. Similar to, but incompatible with, SIMMs.
Domain name service is the means by which a name (like or gets converted into a real Internet address that points to a particular machine.
A disk operating system manages disks and other system resources. Sort of a subset of OSes, sort of an archaic term for the same. MS-DOS is the most popular program currently calling itself a DOS. CP/M was the most popular prior to MS-DOS.
In a denial of service attack, many individual (usually compromised) computers are used to try and simultaneously access the same public resource with the intent of overburdening it so that it will not be able to adequately serve its normal users.
To download a file is to copy it from a remote computer to your own. The opposite is upload.
The DOS currently produced by Caldera (originally produced by Design Research as a successor to CP/M) designed to work like MS-DOS. While similar to CP/M in many ways, it utilizes simpler commands. It provides only a CLI, but either Windows 3.1 or GEOS may be run on top of it to provide a GUI. It only runs on x86 based machines.
A driver is a piece of software that works with the OS to control a particular piece of hardware, like a printer or a scanner or a mouse or whatever.
Depending upon whom you ask, DRM can stand for either Digital Rights Management or Digital Restrictions Management. In either case, DRM is used to place restrictions upon the usage of digital media ranging from software to music to video.
The Document Template Mark-up Language is a subset of SGML and a superset of HTML used for creating documents that dynamically adapt to external conditions using its own custom tags and a little bit of Python. Note that it is quite different from the similarly named DHTML.