Looking back: what is a poem?

So, many weeks and a unit's worth of content later, we're just about done studying poetry. We've looking at its lingual tropes, figurative language, meanings, and analyses of content, structure, and more. Yet through all of this, we've yet to answer one of the first questions we asked ourselves: what is a poem?

Here is a list of 50+ definitions that we first used to consider the definition of poetry. The meanings provided range from literal to ironic, to humorous or even poetic themselves. "Poetry is the rhythmical creation of beauty in words," Edgar Allen Poe exclaims, but really, is rhythm necessary? Or even beauty? Could a poem be ugly, if it wanted to be?

I myself tend to like the idea, "If you even have to ask if it's poetry, then it is." Some poems are clear, with established meter, form, and rhythm. Others, are less so - but does that make them any less of poetry? Take, for example, this piece by Charles Simic:

"I am the last . . ."

BY CHARLES SIMIC

I am the last Napoleonic soldier. It's almost two hundred years later and I am still retreating from Moscow. The road is lined with white birch trees and the mud comes up to my knees. The one-eyed woman wants to sell me a chicken, and I don't even have any clothes on. 
       The Germans are going one way; I am going the other. The Russians are going still another way and waving good-by. I have a ceremonial saber. I use it to cut my hair, which is four feet long.

This reads almost completely as prose. There aren't line breaks or formal structure as you would expect; it's just the page and the words. Yet, still, it has the feel of poetry - and thus I must concluded that it is. After all, as Simic himself said, the poetry is not the words; it is the power behind them.

Poetry is an orphan of silence. The words never quite equal the experience behind them.