What Exactly is a Poem Anyway?

One of the things a poet needs to think about is the question of just what makes a poem a poem. Your conception of what poetry is will determine what type of poetry you will write, what form or forms it will take, what it looks like on the page, what themes or ideas you'll take on and a lot of other things.
Robert Frost, who knew a few things about poetry, insisted that it had to rhyme. Writing poetry without rhyming, he said, is like playing tennis without a net. Most contemporary poets would now disagree with Frost; indeed, his idea was a minority position even when he made it. The popular write-from-the-soul books usually state that anything goes as long as it comes direct from the gut. Others suggest that poetry has to include all of the great technical innovations of the past: regular rhythm, iambic pentameter, metric line structure and the rest.
Let's try something. Read the following and determine whether or not it is a poem:
Nightmare #13
Get your cut throat off my knife.
That's by Diane DiPrima who calle it a poem and published it as one. Does it strike you as a genuine poem?
I'd have to argue that it qualifies. Sure, it's a single line but it has all of the things we generally associate with poems: there's a speaker, a dramatic situation, a few major symbols and a central idea. It also has rhythm and structure. It is concise, precise and suggests more than it states.
Good poetry does all of those things.
Can a single word be a poem:
Where Would I Be Without My Woman?
Morocco
That's by George Mattingly and again I'd have to argue that he's pulled off something major here; a single word that becomes a poem. If you don't think he has, try substituting the word "Boise" for Morocco. Or Birmingham. Yes, one word can be a poem -- if it's the right word. Morocco has a set of suggestions and ramifications to it, it has a culture, an allure, that makes it work.
Of course, both of these poems depend on their title for meaning, but that's true of many poems and it's one of the things a beginning poet needs to learn: the title is crucial. Choosing the right one can make your poem as strongly as the wrong one can break it.
What exactly is a poem, then? It's a piece of writing that contains most of the following:
Implication - it suggests rather than states
symbolism - it contains words that suggest more than their literal meanings.
Rhythm or rhythms -- it pulses, moves like a dance. Often it plays tricks with its rhythm; just as you think you've got it figured out, it gives you a variation.
Honesty - it comes from deep within its creator
Structure - it doesn't just fall out of a pocket. It is planned.
imagery - it contains precise language that appeals to our senses.
Sound values - the poem uses sound as a tool
Metaphor and simile - the poem often uses comparisons as a meaning device.
Multiple meanings - it connects with the reader on unconscious levels that generate more than one way of looking at things.
Effects - the effect of a poem is its emotional impact. It is what it makes us feel.
Tone - a poem reflects its author's way of looking at the material. It can be humorous, tragic, ironic, and so on.
Form - a poem has a definite form. One of the differences between poetry and other types of writing, though, is that each poem creates its own form.
If a piece of writing has all or most of these things, it's pretty safe to say it's a poem. As Paul Morris once said, "A poem is a lie trying to become true." It's a lie because it is made up and it is trying to become true on an intellectual or emotional level; it hits us in an honesty place in an honest way and that is its truth.

Exercise:

Bearing in mind that good poems are not written but are instead rewritten, try the following:
Take one of your old poems and read it over carefully. Check to see if it contains all of the elements listed above. If it does not, ask yourself if it would be more effective if you added them.
As an exercise, revise the poem so that it contains all of the elements in the list. Then keep the ones that help and remove the ones that hurt the overall poem. Remember, when you make changes, you can always change it back.
Oscar Wilde once described a day's work by saying he spent all morning putting in a comma and all afternoon taking it out. That's the revision process right there.