format (n.) Look up format at
1840, "shape and size" (of a book), via French format (18c.), ultimately from Modern Latin liber formatus "a book formed" in a certain shape and size, from past participle of formare "to form," from forma "form, shape" (see form (n.)). Extended to computers by 1955.
format (v.) Look up format at
"arrange into a format," 1964, in reference to electronic computing, from format (n.). Related: Formatted; formatting.