Hamilton, Essential Literary Terms (198-225) -- Jerz: EL150 (Intro to Literary Study)
"Rhyme is the repetition in two or more nearby words of the last stressed vowel and all of the syllables that follow it."
I think that rhyme is a very important factor when writing or reading poetry. This is not always the case for a lot of famous poetry does not rhyme, but it adds to the reading. It is interesting that you have to use words that have certain vowel sounds and syllables that follow the word.
"you have to use words that have certain vowel sounds" -- It's not so much that you HAVE to do this, it's that rhyme is just one of many tools in the skilled poet's toolbox than rhyme. Even if you aren't interested in writing literary poetry, being able to recognize when a poet is using a particular tool can help you interpret a poem more knowledgeably. (Note that I didn't say "interpret a poem correctly" -- that's because poetry is supposed to have ambiguity, and that means different readers will interpret it differently.)