epigram

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A short, witty poem expressing a single thought or observation.
2. n. A concise, clever, often paradoxical statement. See Synonyms at saying.
3. n. Epigrammatic discourse or expression.

Century Dictionary and Cyclopedia

1. n. In Gr. lit., a poetical inscription placed upon a tomb or public monument, as upon the face of a temple or public arch. The term was afterward extended to any little piece of verse expressing with precision a delicate or ingenious thought, as the pieces in the Greek Anthology. In Roman classical poetry the term was somewhat indiscriminately used to designate a short piece in verse; but the works of Catullus, and especially the epigrams of Martial, contain a great number with the modern epigrammatic character.
2. n. Hence In a restricted sense, a short poem or piece in verse, which has only one subject, and finishes by a witty or ingenious turn of thought; hence, in a general sense, an interesting thought represented happily in a few words, whether verse or prose; a pointed or antithetical saying.

Wiktionary

1. n. An inscription in stone.
2. n. A brief but witty saying.
3. n. A short, witty or pithy poem.

GNU Webster's 1913

1. n. A short poem treating concisely and pointedly of a single thought or event. The modern epigram is so contrived as to surprise the reader with a witticism or ingenious turn of thought, and is often satirical in character.
2. n. An effusion of wit; a bright thought tersely and sharply expressed, whether in verse or prose.
3. n. The style of the epigram.

WordNet 3.0

1. n. a witty saying