dithyramb

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A frenzied, impassioned choric hymn and dance of ancient Greece in honor of Dionysus.
2. n. An irregular poetic expression suggestive of the ancient Greek dithyramb.
3. n. A wildly enthusiastic speech or piece of writing.

Century Dictionary and Cyclopedia

1. n. A form of Greek lyric composition, originally a choral song in honor of Dionysus, afterward of other gods, heroes, etc. First given artistic form by Arion (about 625 b. c.) and rendered by cyclic choruses, it was perfected, about a century later, by Lasos of Hermione, and at about the same time tragedy was developed from it in Attica. Its simpler and more majestic form, as composed by Lasos, Simonides, Bacchylides, and Pindar, assumed in the latter part of the fifth century a complexity of rhythmical and musical form and of verbal expression which degenerated in the fourth century into a mimetic performance rendered by a single artist. From these different stages in its history the word dithyramb has been used in later ages both for a nobly enthusiastic and elevated and for a wild or inflated composition. In its distinctive form the dithyramb is ἀλλοιόστροφος (consists of a number of strophes no two of which are metrically identical).

Wiktionary

1. n. A choral hymn sung in ancient Athens in honor of the god Dionysus.
2. n. A poem or oration in the same style.

GNU Webster's 1913

1. n. A kind of lyric poetry in honor of Bacchus, usually sung by a band of revelers to a flute accompaniment; hence, in general, a poem written in a wild irregular strain.

WordNet 3.0

1. n. a wildly enthusiastic speech or piece of writing
2. n. (ancient Greece) a passionate hymn (usually in honor of Dionysus)