The story
The term was invented at Stanford and is based on Swiss computer scientist Niklaus Wirth's nickname of Bucky. Wirth suggested this keyboard feature in the mid-1960s.
Etymology from Wiktionary, CC BY-SA 4.0.
bucky bit
Today it means: A bit (binary digit) in the binary representation of a text character that is set by means of a modifier key on the keyboard, allowing numerous characters to be produced by different combinations of keypresses. Full definition →