prose poem is

I would have placed emphasis on the subversive character of prose poetry. For me, it is a kind of writing determined to prove that there’s poetry beyond verse and its rules. Most often it has an informal, playful air, like the rapid, unfinished caricatures left behind on café napkins. Prose poetry depends on a collision of two impulses, those for poetry and those for prose, and it can either have a quiet meditative air or feel like a performance in a three-ring circus.

—Charles Simic, "Essay on the Prose Poem," delivered on June 1, 2010 at The Poetry Festival in Rotterdam.