Poetry is a form of literature that follows specific forms to create a rhythm and/or rhyme scheme. Without those elements we have the poetic form known as “free verse,” but it retains an elevated language that still makes it poetry.
The noun poetry goes all the way back to the Latin poesis, meaning both "poetry" and "making." It usually refers to the specific genre of poetic works, a wide variety of styles tied together by the structured use of the language, but is also used to describe any especially beautiful language. The French writer Voltaire once said, “Poetry is the music of the soul, and, above all, of great and feeling souls.”