Of the many definitions of poetry, the simplest is still the best: 'memorable speech'.
Quotes from introduction to The Poet's Tongue — W. H. Auden
Attribution
Quotes and notes from Wikiquote: W. H. Auden (page history), available under CC BY-SA 4.0.
Quotes and notes from Wikiquote: W. H. Auden (page history), available under CC BY-SA 4.0.