Name Description
OEM Stands for "Original Equipment Manufacturer." This refers to a company that produces hardware to be marketed under another company's brand name.
Offline: When a computer or other device is not turned on or connected to other devices, it is said to be "offline." This is the opposite of being "online," when a device can readily communicate with other devices.

Offline can also mean not being connected to the Internet. When you disconnect from your ISP or pull out the Ethernet cable from your computer, your computer is offline. Some programs, such as Web browsers and e-mail programs, have an option to "Work Offline." This option disables the program's network connection, meaning no data can be transmitted to or from the computer.
Online: In general, when a machine is "online," it is turned on and connected to other devices. For example, when a network printer is online, computers connected to that network can print from it. Other devices, such as scanners, video cameras, audio interfaces, and others are said to be online when they are running and connected to a computer system.

Recently, however, the term "online" usually means being connected to the Internet. The connection can be through a phone line, using a dial-up or DSL modem, a cable line via a cable modem, or through a wireless connection. A computer can also be online via a connection to a computer network. Technically, computers that are on a network are online even if they are not connected to the Internet.
Operating System: Also known as an "OS," this is the software that communicates with computer hardware on the most basic level. Without an operating system, no software programs can run. The OS is what allocates memory, processes tasks, accesses disks and peripherals, and serves as the user interface.
Optical Drive: In the computer world, "optical" refers to lasers, which can "see" and read data on optical discs. These discs include CDs and DVDs, which are made up of millions of small bumps and dips. Optical drives have lasers that read these bumps and dips as ones and zeroes, which the computer can understand.

Some common types of optical drives include CD-ROM, CD-RW, DVD-ROM, DVD-RW, and Blu-ray drives.
OS X: Mac OS X, is the current version of the operating system used on Apple Macintosh computers.
OSD: OSD is short for "On Screen Display." An OSD is an onscreen menu included with most monitors that allows users to make adjustments to the display. Common OSD settings include brightness, contrast, and color calibration adjustments. Some monitors also include positioning settings and tilt control. You can activate the OSD by pressing the MENU button on the side of the monitor. Once the OSD appears, you can navigate through the menu options and make adjustments using the plus (+) and minus (-) buttons.
Outbox: An Outbox is where outgoing e-mail messages are temporarily stored. While you are composing a message, most mail programs automatically save a draft of your message in the Outbox. The message is then stored in the Outbox until it is successfully sent to the recipient. Once the message has been sent, most e-mail programs move the message to the "Sent" or "Sent Messages" folder. While the terms "Outbox" and "Sent Messages" are often used synonymously, technically they have different meanings.
Output Device: Any device that outputs information from a computer is called, not surprisingly, an output device. Since most information from a computer is output in either a visual or auditory format, the most common output devices are the monitor and speakers. These two devices provide instant feedback to the user's input, such as displaying characters as they are typed or playing a song selected from a playlist.
Overclocking: Overclocking involves increasing the clock speed of the computer's CPU past the rate at which it was originally designed to run.
Overwrite: The term "overwrite" refers to replacing old files with new ones. If you try to save a document with the same filename as an existing document, you may be asked if you want to overwrite the file. If you click OK, the old document will be overwritten by the new one. Similarly, when moving files to a folder, the operating system may ask you if you would like to overwrite existing files with the same filenames. If you choose select Overwrite, the old files will be replaced by the new ones.