Forms: 6–7 terset, 7 tercett, (terzetta), 7–9 terzet, 8 -ett, (9 terzette), 7–9 tiercet, 9 tercet. [ad. It. terzetto, dim. f. terzo (:—L. tertius) third + -etto, -ET. Thence also obs. F. tiercet (c. 1500 in Jean Le Maire) and mod.F. tercet (17th c. in Boileau), whence the later Eng. forms.]
1. Pros. A set or group of three lines riming together, or bound by double or triple rhyme with the adjacent triplet or triplets; spec. a. each of the triplets of the Italian TERZA RIMA; b. each of the two triplets usually forming the last six lines of a sonnet.
1598. Florio, Terzetto, a terset of rymes, rymes that ryme three and three.
1656. Earl Monm., trans. Boccalini’s Advts. fr. Parnass., I. lxxvi. (1674), 93. The … Princes … were proof against every pungent Terzetta. Ibid., II. xiv. 154. The pleasant Tersets.
1755. Johnson, Tiercet … triplet; three lines.
1838–9. Hallam, Hist. Lit., II. II. v. § 44. 208. The first lines or quartets of the sonnet excite a soft expectation, which is harmoniously fulfilled by the tercets or last six lines.
1885. A. J. Butler, Dante, Paradise, XIX. 257, note. Observe the structure of this and the following tercets.
2. Mus. a. A third. (? An error.) b. A triplet (Cent. Dict., 1891).
1706. Phillips (ed. Kersey), Tercet, a Third in Musick. [So 1721 Bailey, 1775 Ash, and many 19th c. Dicts.]
