pigeonhole

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A small compartment or recess, as in a desk, for holding papers; a cubbyhole.
2. n. A specific, often oversimplified category.
3. n. The small hole or holes in a pigeon loft for nesting.
4. v. To place or file in a small compartment or recess.
5. v. To classify mentally; categorize.
6. v. To put aside and ignore; shelve.

Century Dictionary and Cyclopedia

1. n. One of the holes in a dove-cote or pigeon-house through which the birds pass in and out.
2. n. Hence A little compartment or division in a case for papers, a bureau, a desk, or the like.
3. n. One of a series of holes in an arch of a furnace through which the gases of combustion pass.
4. n. One of a series of holes in the block at the bottom of a keir through which its liquid contents can be discharged.
5. n. plural An old English game, resembling modern bagatelle, in which balls were rolled through little cavities or arches.
6. n. In printing, an over-wide space between printed words. Also called rat-hole.
7. To place or file away in a pigeonhole; hence, to lay aside for future consideration; hence, to lay aside and ignore or forget; “shelve”; treat with intentional neglect: as, to pigeonhole an application for an appointment; to pigeonhole a scheme.

Wiktionary

1. n. A nook in a desk for holding papers.
2. n. One of an array of compartments for sorting post, messages etc. at an office, or college (for example).
3. n. A hole, or roosting place for pigeons.
4. v. To categorize; especially to limit or be limited to a particular category, role, etc.
5. v. To put aside, to not act on (proposals, suggestions, advice).

GNU Webster's 1913

1. n. An old English game, in which balls were rolled through little arches.
2. n. A small compartment in a desk or case for the keeping of letters, documents, etc.; -- so called from the resemblance of a row of them to the compartments in a dovecote.
3. v. To place in the pigeonhole of a case or cabinet; hence, to put away; to lay aside indefinitely.

WordNet 3.0

1. v. place into a small compartment
2. v. treat or classify according to a mental stereotype
3. n. a small compartment
4. n. a specific (often simplistic) category