"notch, groove, slit," late 15c., nyke, of unknown origin, possibly influenced by M.Fr. niche "niche." The verb is first attested 1520s. Sense of "to steal" is from 1869, probably from earlier slang sense of "to catch, take unawares, arrest" (1620s). Nick of time is first attested 1640s, possibly from an old custom of recording time as it passed by making notches on a tally stick, though the general sense of "critical moment" is older (1570s) than the phrase.