1. the 20th letter of the modern english alphabet.
2. any of the speech sounds represented by the letter t.
3. the 20th in a series.
4. something shaped like the letter T.
5. to a T perfectly; precisely: this actor fits the role to a T.
6. top quark

1. the twentieth letter of the basic modern latin alphabet.
2. voiceless alveolar plosive.
3. time
4. tonne
5. (lisp) the atom representing true, as opposed to nil.
6. the twentieth letter of the english alphabet, called tee and written in the latin script.
7. the ordinal number twentieth, derived from this letter of the english alphabet, called tee and written in the latin script.

1. the twentieth letter of the english alphabet, is a nonvocal consonant. with the letter h it forms the digraph th, which has two distinct sounds, as in thin, then. see guide to pronunciation, §§262-264, and also §§153, 156, 169, 172, 176, 178-180.

1. an abbreviation of territory, testament, thursday, titus (a book of the new testament), tuesday, turkish; in medicine, of tension of the eyeball; [lowercase] of tome, ton, town, township, transitive, tun, tungsten, and of the latin tempore, in the time (of).
2. an abbreviation of thrice illustrious.
3. the twentieth letter and sixteenth consonant of the english alphabet.
4. the value of the sign has been practically the same through the whole history of its use; it denotes the surd (or breathed) mute (or check) produced by a complete closure (with following breach or explosion) between the tip of the tongue and a point on the roof of the mouth either close behind or not far from the bases of the upper front teeth. its corresponding sonant or voiced mute is d, and its nasal is n (see these letters). they are oftenest called dental or teeth-sounds, though the teeth have really no part in their production; hence also, and better, lingual, or front lingual, or tongue-tip, etc. they are much more common elements of our utterance than either of the other two classes, palatal (k, g, ng) or labial (p, b, m); they constitute, namely, about 18 per cent. of the sounds we make (t nearly 6 per cent., d nearly 5, n nearly 7), against palatal 4 per cent., and labial 6½. A sound which our ears would at once recognize and name as a t-sound is producible in other positions of the organs than that described above—namely, at points further back on the roof of the mouth, and with parts of the tongue behind the tip, and even of its under surface. hence the occurrence in some languages of more than one t, distinctly recognized as separate members of the spoken alphabet (so two in sanskrit, etc., and even four in siamese); our own t also which forms the first part of the compound ch (= tsh) is slightly but constantly different from our t elsewhere. as in many other languages (and partly by direct inheritance from french, and even from later latin, alterations), the t in english shows a tendency to become palatalized and converted into a sibilant when followed by palatal sounds, as i, e, y. hence, in many situations, it combines with such sounds, either regularly or in rapid utterance, producing the ch-sound, as in question, mixture (compare the corresponding conversion of s to sh, under S); and even, in a great number of words having the endings -tion, -tious, -tial, etc., it becomes a sibilant and makes the sh-sound, as in nation, factious, partial, etc. T also, like others of our consonants, frequently occurs double, especially when medial: thus (from fit) fitted, fitter, fitting. with h, t forms the digraph th, which has the position and importance of a fully independent element in the alphabet, with a double pronunciation, surd and sonant (or breathed and voiced): surd in thin, breath; sonant in this, breathe—both as strictly unitary sounds as t and d, or s and z. they are related with t and s, etc., as tongue-tip sounds, especially with s and z as being fricative and continuable; but they are of closer position than the latter, the closest that can be made without actual stoppage of the breath, and are usually formed with the tongue thrust further forward, against or even beyond the teeth: hence their substitution for s and z by persons who lisp. in regard to their grade of closure, they are akin to f and v, and belong in one class with these (oftenest and best called spirants). as an f comes in part from an aspirated p, or ph, so also the th-sounds from an aspirated t; and in this way they have obtained their usual representation: the greek
5. as a medieval numeral, 160; with a line over it (T), 160,000.
6. an abbreviation: [lowercase] in musical notation, of tenor, tempo (as a t., a tempo), tutti, and tasto (as t. s., tasto solo).
7. [lowercase] in a ship's log-book, of thunder
8. [lowercase] in zoology, of typacanthid.
9. in mathematics: [lowercase] of time; of tensor, a functional symbol.
10. an abbreviation of tasto solo.
11. A white clay pipe with the initials T. D. on the bowl. said to be due to a legacy left by the eccentric “lord” timothy dexter of Newburyport, mass., in order to perpetuate his name. by extension, T. D. means clay pipe. dialect notes, iii. iii.
12. an abbreviation of topographical engineer.
13. an abbreviation of till forbidden.
14. an abbreviation of type genus.
15. an abbreviation of the latin tinctura opii, tincture of opium; of turn over; of topographical office (of the ordnance survey england). in the last sense also written T-O.
16. an abbreviation of till sale.
17. A symbol suggested by von behring for a principle alleged to be present in the tubercle bacillus which exerts a catalytic and zymogenic action.
18. something made or fashioned in the form of a T, as a piece of metallic pipe for joining two lines of piping at right angles to each other. also written tee, and sometimes tau. see T-bandage, T-beard, T-bone, T-cloth, T-iron, T-joint, T-rail, T-square.
19. A form of -ed, -ed, in certain words. see -ed, -ed.

1. a unit of weight equivalent to 1000 kilograms
2. thyroid hormone similar to thyroxine but with one less iodine atom per molecule and produced in smaller quantity; exerts the same biological effects as thyroxine but is more potent and briefer
3. one of the four nucleotides used in building dna; all four nucleotides have a common phosphate group and a sugar (ribose)
4. the 20th letter of the roman alphabet
5. a base found in dna (but not in RNA) and derived from pyrimidine; pairs with adenine
6. hormone produced by the thyroid glands to regulate metabolism by controlling the rate of oxidation in cells