An effusion is an explosion of something, usually words, ideas, or emotions. Judy Garland regularly inspired an effusion of cheers from her enraptured audiences. The ovations were "effusive."
Mozart is known for the effusion of notes he could produce at a moment's notice—and all without erasing. A heated argument can produce an effusion of words from both sides. The volcano's eruption was an effusion of smoke and fire. The verb form of the word is "effuse": After the high-school musical, your mother effused about your singing. Her comments were an effusion of praise. Your father, on the other hand, was less effusive—but he did like the dancing.
