Poetry is a type of art form and a type of literature.
Poetry uses the qualities of words, in different ways, to be artistic.
Poetry can be as short as a few words, or as long as a book. A poem as short as one line is called a monostich. A poem that is as long as a book is an epic.
There are many "poetic forms" (forms of poetry). Some of forms are: Sonnet, Haiku, Ballad, Stev, Prose poem, Ode, Free verse, Blank verse, thematic, limerick and nursery rhymes.
Poetry can be used to describe (comparing, talking about, or expressing emotion) many things. It can make sense or be nonsense, it can rhyme or not. It can have many shapes and sizes; it can be serious or funny.
"To say something poetically" means to give information in an artistic way.