A unit or group of three lines of verse which are rhymed together or have a rhyme scheme that interlaces with an adjoining tercet. Sidelight: The sestet, or second part of a Petrarchan sonnet, often consists of two tercets. Sidelight: A tercet is used as an envoi in a sestina.(See also Terza Rima)

A tercet is three lines of poetry forming a stanza or complete poem. Haiku is an example of an unrhymed tercet poem.

A triplet.

the cardinal number that is the sum of one and one and one