Rhyme scheme

A rhyme scheme is the pattern of rhymes at the end of each line of a poem or song. It is usually referred to by using letters to indicate which lines rhyme; lines designated with the same letter all rhyme with each other.

An example of the ${\displaystyle \mathrm {ABAB} }$ rhyming scheme, from "To Anthea, who may Command him Anything", by Robert Herrick:

Bid me to weep, and I will weep		${\displaystyle \mathrm {A} }$
While I have eyes to see		${\displaystyle \mathrm {B} }$
And having none, yet I will keep		${\displaystyle \mathrm {A} }$
A heart to weep for thee		${\displaystyle \mathrm {B} }$