A dithyramb is a speech or piece of writing that bursts with enthusiasm. A dithyramb is full of passion and purpose, so save it for a special occasion.
The next time you hear a wildly enthusiastic speech, pull this word out of your hat to describe it. The Greek original was the name for a passionate choral hymn, typically to Dionysus. Since then, dithyramb came to mean a poem with similar passion, and then any type of writing or speech that bursts with enthusiasm. A love letter could be called a dithyramb. A powerful speech on behalf of justice could be called a dithyramb. Dithyrambs are passionate.