A bit, also known as a Shannon, is the basic unit of information in computing and digital communications. A bit can have only one of two values, and may therefore be physically implemented with a two-state device. These values are most commonly represented as either a 0or1. The term bit is a portmanteau of binary digit.

The two values can also be interpreted as logical values (true/false, yes/no), algebraic signs (+/−), activation states (on/off), or any other two-valued attribute. The correspondence between these values and the physical states of the underlying storage or device is a matter of convention, and different assignments may be used even within the same device or program. The length of a binary number may be referred to as its bit-length.

In information theory, one bit is typically defined as the uncertainty of a binary random variable that is 0 or 1 with equal probability, or the information that is gained when the value of such a variable becomes known.

In quantum computing, a quantum bit or qubit is a quantum system that can exist in superposition of two classical (i.e., non-quantum) bit values.

A bit is a unit of information storage on a computer.

Bit or BIT may also refer to:

Tools and engineering

Arts and entertainment

Organisations

Education

A bit is a type of horse tack used in equestrian activities, usually made of metal or a synthetic material, and is placed in the mouth of a horse or other equid and assists a rider in communicating with the animal. It rests on the bars of the mouth in an interdental region where there are no teeth. It is held on a horse's head by means of a bridle and has reins attached for use by a rider.

Basic types

Although there are hundreds of design variations, the basic families of bits are defined by the way in which they use or do not use leverage. They include: