1. A machine that can be programmed to manipulate symbols.
2. A device that performs high-speed mathematical or logical operations or that assembles, stores, correlates, and otherwise processes information.
3. Someone who utilizes a programmable electronic machine that has special procedures for accomplishing results: Computers can perform complex and repetitive procedures quickly, precisely, and reliably; as well as, quickly storing and retrieving large amounts of data.

The physical components from which a computer is constructed and which provide electronic circuits and input/output devices are known as "hardware".

Most computers have four types of hardware components: CPU, input, output, and memory.

The CPU, or central processing unit, executes programs known as "software" which direct the computer what to do.

Input and output, I/O, devices allow the computer to communicate with the user and the outside world.

There are several kinds of memory for computers that include fast, expensive, short term memory, known as RAM, to hold intermediate results, and slower, cheaper, long-term memory; such as, magnetic disk and magnetic tape, to hold programs and data between jobs.

Origin of the word computer

The term computer is a word which was formed in English from the verb compute and it has a recorded history going back to 1646, when it was used to mean "a person who computes".

In 1897, the word was first recorded as "a calculating machine", although that particular machine, which was "of the nature of a circular slide rule", did not resemble a modern computer.

Humans were the earliest computers. These "counting persons" were professionals who worked with numbers and were credited with great accuracy. The early computing was manual and involved the use of such counting tools as the abacus and a variety of slide rules.

When adding machines were developed, the man or woman who computed with one of these "rapid" devices, often called the counting machine a computer.

1. A disorder in which some people spend an excessive amount of time on the internet: Some examples of computer addicts involve those who are involved in playing computer games, accessing social websites in an attempt to overcome anxieties or to reduce isolation or loneliness, and to distract themselves from other overwhelming problems.

Some people may be accused of being computer addicts because they are engrossed in achieving more objectives via the internet and their computers than is possible with any other tool or device.

2. Etymology: from Latin com-, "with" and putare, "to reckon" or "to think" + ad-, "to" + dicere, "to say, to declare".

A branch of science that promotes knowledge which is concerned with information processes, the structures and procedures that represent these processes, and their implementation in the various information-processing systems of computers.

1. A condition related to prolonged computer monitor use; such as, people who are viewing computer screens who tend to blink less and open their eyes more widely, all of which can result in dryness of the eyes, fatigue, burning, difficulty in focusing, headaches, etc.
2. CVS is caused by the decreased blinking reflex of the eyes while working long hours focusing on computer screens.

The normal blinking rate in human eyes is about 16–20 blinks per minute and recent studies have shown that the blinking rate decreases to as low as 6–8 blinks a minute for people who are working on computer screens for long periods and this can lead to an irritating condition called dry eyes.
3. A variety of problems related to prolonged viewing of a computer screen.

Short term effects include dry eyes, blurred vision, eye fatigue and excessive tearing.

Long term effects include migraines, cataracts, and visual epilepsy.

Some solutions include keeping reflections and glare to a minimum and to provide a non-fluorescent, uniform light source.

Special lamps are available that maintain the proper light around the monitor and generate light at much higher frequencies than regular light bulbs.

Glasses Can Correct Near and Far, but What About Those Screens in Between?

1. A computer that performs calculations and logical operations with quantities represented as digits, usually in the binary number system.
2. A device capable of accepting data in the form of facts and figures, manipulating them in a prescribed way, and supplying the results of these processes as meaningful information.

This device usually consists of input and output devices, storage, arithmetic and logic units, and a control unit. Usually an automatic, stored-program machine is implied.

1. A programmable machine that receives input, stores and manipulates data, and provides output in a useful format.
2. An apparatus that receives, processes, and presents information.

The two basic types of computers are analog and digital.

Although generally not regarded as such, the most prevalent computer is the simple mechanical analog computer, in which gears, levers, ratchets, and pawls perform mathematical operations; for example, the speedometer and the watt-hour meter (used to measure accumulated electrical usage).

The general public has become much more aware of the digital computer with the rapid proliferation of the hand-held calculator and a large variety of intelligent devices and especially with exposure to the Internet and the World Wide Web.

A machine that uses electronic circuitry in the main computing element to perform arithmetic and logical operations on digital data; for example, data represented by numbers or alphabetic symbols.

This is done automatically with an internally stored program of machine instructions.

Such instruments are distinguished from calculators on which the sequence of instructions is externally stored and is impressed manually (desk calculators) or from tape or cards (card-programmed calculators).

A large, powerful, high-speed computer frequently used as the central computer at an institution or company, or government agency.

A machine aid to computation in which variables are represented as continuously variable displacements or motions of mechanical elements; such as, gears and shafts.

Personal Computer Computer

A type of computer used in scientific applications, characterized by complex computations involving floating-point arithmetic.