In verse drama, two consecutive lines that rhyme with each other, usually at the end of a scene or a speech, like a closing phrase that lodges in the memory.
In Othello
I have 't. It is engendered. Hell and night / Must bring this monstrous birth to the world's light.
The two lines end in "night" and "light", and the rhyme closes the act like a sentence that lodges in the memory. Iago's dark promise thus takes on the finish of a magic formula.
Act I: Venice, the Night Accusation and the Senate's Judgment, Iago
If she be fair and wise, fairness and wit, / The one's for use, the other useth it.
Act II: Cyprus, the Storm and Cassio's Fall, Iago
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