A rhyming couplet is a pair of lines of meter in poetry. They usually consist of 2 lines that rhyme and have the same meter. The term couplet comes from the French word, meaning "two pieces of iron riveted or hinged together". Rhyming couplets do not have to be just 2 lines. As long as the lines are in AABBCCDDEE Etc.
An Essay on Criticism
By Alexander Pope
True wit is nature to advantage dress'd;
What oft was thought, but ne'er so well express'd.