also pigeonhole, 1570s as "a small recess for pigeons to nest in," from pigeon + hole (n.); later "hole in a dovecote for pigeons to pass in and out" (1680s). Extended meaning "a little compartment or division in a writing desk," etc. is from 1680s, based on resemblance. Hence, "an ideal compartment for classification of persons, etc." (by 1879). The verb is from 1840, "place or file away in a pigeon-hole." The figurative sense of "lay aside for future consideration" is by 1854, that of "label mentally" by 1870.
[Y]ou will have an inspector after you with note-book and ink-horn, and you will be booked and pigeon-holed for further use when wanted. ["Civilisation—The Census," Blackwood's Magazine, Oct. 1854]