Bit
A bit (binary digit) is the most fundamental unit of digital information, representing a single binary value of either 0 or 1. All digital data — from text to video — is ultimately stored and transmitted as sequences of bits.
History
The term 'bit' was coined by mathematician John Tukey in 1947 and popularized by Claude Shannon in his 1948 paper 'A Mathematical Theory of Communication.' Eight bits make one byte, which can represent 256 different values (0-255).