In computing, a bit (short for binary digit) is the smallest unit of data that a computer can process and store. It is always in one of two physical states, usually represented by a 0 or 1, and is stored in memory through the use of capacitors that hold electrical charges. Bits are usually assembled into a group of eight to form a byte, which contains enough information to store a single ASCII character. Although a computer might be able to test and manipulate data at the bit level, most systems process and store data in bytes.

Computers usually manipulate bits in groups of a fixed size, conventionally named "words". The number of bits in a word varies with the hardware design and is typically between 8 and 80 bits, or even more in some specialized computers.

In summary, a bit is the smallest unit of data that a computer can process and store, and it is usually grouped into bytes for processing and storage.