[acronym, 'End Of File']
n. 1. [techspeak] Refers esp. to whatever out-of-band value is returned by C's sequential character-input functions (and their equivalents in other environments) when end of file has been reached. This value is -1 under C libraries postdating V6 UNIX, but was originally 0.
2. Used by extension in non-computer contexts when a human is doing something that can be modeled as a sequential read and can't go further.
"Yeah, I looked for a list of 360 mnemonics to post as a joke, but I hit EOF pretty fast; all the library had was a JCL manual."
See also EOL.