Definition of "dithyramb"

dithyramb

/ˈdɪθ.ɪ.ɹæm/

noun
plural dithyrambs
1. A raucous and ardent choral hymn sung in ancient Athens in honor of the god Dionysus.
2. A poem or oration in the same style.
  Quotations
  While those who drown a truth’s empiric partIn dithyramb or dogma turn frenetic;— Than whom no writer could be less poeticHe left this lesson for all verse, all art.
  1969, Robert Conquest, “George Orwell”, in Arias from a Love Opera, and Other Poems, Macmillan, page 32
3. An impassioned speech; a rant.