CPU - Central Processing Unit - the heart (brains) of the computer system.  It is comprised of the control unit, the arithmetic logic unit, and temporary storage (RAM).

DOS - Disk Operating System - was the first widely-installed operating system for personal computers developed for IBM by Microsoft.  It is software used in most computer systems to manage storage devices as well as data of any kind, including files.  It is referred to as a "disk" operating system because the storage devices are made of rotating platters.

IDE - Integrated Development Environment - a system where you can control the editing and compiling from one program.

LAN - Local Area Network - a set of computers connected in order to share programs and storage space.  "Local" implies that the network is contained within a relatively small space, such as a classroom, an office, one section of the building, or one building.

OOP - Object Oriented Programming - the use of small, reusable components to construct large software systems.

OS - Operating System - the program that manages all the other programs in a computer.   Some popular operating systems include MS-DOS, Windows 98/2000/NT/XP, MacOS, Unix, and Linux.

RAM - Random Access Memory - temporary memory lost when the computer is turned off.

ROM - Read Only Memory - hardwired memory which cannot be changed.  Contains the system directions.