Poetry 2-Genus of Poetry
I began with calling poetry an art, in that poetry is an idealized creation of man. The definition of art is: a selective recreation of reality. A recreation of reality because art is not reality itself, yet reality is it's only subject. Selective because the artist does not portray reality exactly, he chooses which aspects to portray depending upon his values and idealizes those values. Please, don't ask me to define value, I thought about it and I can't do that yet. I have a working definition which I use to judge a value, for now, but I don't understand it well enough to defend the definition. Art is judged good to the extent of the artist's ability to idealize the value(s), and it is appreciated by an individual to the extent that that individual agrees with the value(s).
Then it occurred to me that I can narrow the genus further, poetry is expressed only in one particular medium. You can't paint or sculpt a poem: if you tried, what you'd end up with is a painting or a sculpture based upon a poem, but not a poem itself. At first I wanted to call this medium 'literature', and it's definition was: language arts. In other words, art which is expressed in language (written or oral). But after consulting a great friend, I think this is the wrong concept for this definition. Literature can include history/science/technical textbooks which aren't art, though it's written. But, whatever the label, the definition is correct; so poetry is a language art.