Poetry has anywhere between few and many lines. It may have Iambic Pentameter, rhythm, rhyme, foot, irony, vision, connotation, stanzas and possibly a title. Poetry has syllables, similes, metaphors. It has words, letters, definitions, puns, spaces, and an author, whom may be unknown.
But Poetry is a way to think, to speak upon a piece of paper, which will speak back, giving you the luxury of silence. Poetry is a way to express your hate, sadness, loneliness, envy, joy, lust, or love. To express any emotion to that piece of paper which will not judge you and your deepest feelings, as you scribble across its face, leaving graphite scars. Poetry is a way, to record your observations. Maybe the observation is of a beautiful sunset, a tantrum of the sea, or how the lips of lovers lock so much sweeter than those of others. Poetry is an art. An art that steams from soul, mind and from the heart.
Poetry is like pornography. No true definition, you just know it when you see it.