thirty years.  Associated Words:  tricennial, tricennially.

thorn, n. spine, prickle, brier; torment, plague, infliction.

thornless, a. spineless, inermis.

thorny, a. spiny, briery, prickly; vexatious, troublesome, annoying.

thorough, a. complete, profound.  Antonyms:  superficial, cursory, partial, sciolistic.

thought, n. reflection, cogitation, revery, musing, meditation, consideration, abstraction, imagination, brown study, contemplation, deliberation, introspection, retrospection, lucubration, rumination, preoccupation, excogitation; idea, concept, surmise, inference.

thoughtful, a. contemplative, meditative, reflective, cogitative, wistful, pensive, preoccupied, abstracted; considerate, heedful, circumspect, wary.

thoughtless, a. inconsiderate, careless, unmindful, remiss, rash, inadvertent, indiscreet, heedless, unreasoning.

thousand, n.  Associated Words:  millennium, millennial, chiliad, chiliasm, chiliarchy, chiliarch, chiliast, millenary, millesimal.

thrash, v. thresh.

thread, n. filament, fibre, stamen, staple, pile, raveling, lint, warp, woof, thrum.—­v. thrid.

threadbare, a. napless, pileworn, seedy, trite, hackneyed.

threat, n. menace, threatening, commination, fulmination, intimidation.

threaten, v. menace; augur, forebode, portend; impend, be imminent.

threatening, a. imminent, ominous, impending, minatory, fulminating.

three, n. trio, trinity, triad, ternary, ternion; triplets.  Associated Words:  thrice, treble, trialogue, triarchy, triplicate, triplication, triplicity, trinal, triarchy, tripartition, tripod, triptych, trisect, trisection, trireme, triumvirate, trilogy, triform, triformity, trilling, trilemma.

three-colored, a. tricolored.

three-flowered, a. trifloral, triflorous.

threefold, a. triple.

three-forked, a. trisulcate, trifurcated.

three hundred years. tricentenary.  Associated Words:  tercentenary, tricentenary, tri-centennial.

three languages.  Associated Word:  trilingual.

three-leaved, a. trifoliate, trifoliated.

three-legged stand. trivet, tripod.

three letters. triphthong, trigraph.

three months. trimester.  Associated Words:  trimestral, trimestrial, quarterly.

three-parted, a. tripartite.

three-pointed, a. tricuspidate, tricuspid.

three-pointed spear. trident.

three-sided, a. triangular, trilateral.

three-sided figure. triangle.

three-toothed a. trident, tridentate.

three years. triennium.  Associated Words:  triennial, triennially.

threshold, n. doorsill.

thrift, n. frugality, economy, thriftiness, providence; prosperity.

thriftless, a. wasteful, improvident, extravagant, prodigal.

thrifty, a. sparing, economical, provident, frugal; thriving, prosperous; luxuriant.