Bit (b)
Modern equivalent
1 bit
The fundamental binary digit of digital information holding either a 0 or a 1.
A contraction of binary digit, coined by John Tukey in 1947 and popularised by Claude Shannon the following year in the paper that founded information theory. Its symbol is a lowercase b, against the byte’s capital B, and that single character of difference is responsible for more confusion than anything else in digital measurement: broadband is sold in megabits per second and files are measured in megabytes, so a 100 Mb/s connection downloads at about 12.5 MB/s. The factor of eight is not a trick, merely two conventions meeting. Network engineers count bits because that is what travels down a wire; everyone else counts bytes because that is what a character of text takes up.