To rub, turn; with some derivatives referring to twisting, boring, drilling, and piercing; and others referring to the rubbing of cereal grain to remove the husks, and thence to the process of threshing either by the trampling of oxen or by flailing with flails.
Oldest form *terh1-
, with variant *treh1-
, becoming *trē-
▲ Derivatives include trite, detriment, thrash, trauma, truant.
Full-grade form *ter(ə)-
1. a. trite, triturate; attrition, contrite, detriment from Latin terere (past participle trītus), to rub away, thresh, tread, wear out; b. teredo from Greek terēdōn, a kind of biting worm.
2. Suffixed form *ter-et-. terete from Latin teres (stem teret-), rounded, smooth.
3. Suffixed form *ter-sko-. a. thrash, thresh from Old English therscan, to thresh; b. threshold from Old English therscold, threscold, sill of a door (over which one treads; second element obscure). Both a and b from Germanic *therskan, *threskan, to thresh, tread.
O-grade form *tor(ə)-
1. toreutics from Greek toreus, a boring tool.
2. Suffixed form *tor(ə)-mo-, hole. derma2 from Old High German darm, gut, from Germanic *tharma-.
3. Suffixed form *tor(ə)-no-. turn; attorn, attorney, contour, detour, return from Greek tornos, tool for drawing a circle, circle, lathe.
III. Zero-grade form *tr-. drill1 from Middle Dutch drillen, to drill, from Germanic *thr-.
Variant form *trē-
1. throw from Old English thrāwan, to turn, twist, from Germanic *thrēw-.
2. Suffixed form *trē-tu-. thread from Old English thrǣd, thread, from Germanic *thrēdu-, twisted yarn.
3. Suffixed form *trē-mn̥ (< *treə- or *tr̥ə-) diatreme, monotreme, trematode from Greek trēma, perforation.
4. Suffixed form *trē-ti- (< *treə- or *tr̥ə-) atresia from Greek trēsis, perforation.
Extended form *trī-
1. Probably suffixed form *trī-ōn-. septentrion from Latin triō, plow ox.
2. Suffixed form *trī-dhlo-. tribulation from Latin trībulum, a threshing sledge.
Various extended forms
1. Forms *trō-, *trau-. trauma from Greek trauma, hurt, wound.
2. Form *trīb-. diatribe, triboelectricity, tribology, triboluminescence, trypsin from Greek trībein, to rub, thresh, pound, wear out.
3. Form *trōg-, *trag-. a. trogon, trout from Greek trōgein, to gnaw; b. dredge2 from Greek tragēma, sweetmeat.
4. Form *trup-. trepan1; trypanosome from Greek trupē, hole.
5. Possible form *trūg-. truant from Old French truant, beggar.
[Pokorny 3. ter- 1071.]
To cross over, pass through, overcome.
Oldest form *terh2-
, with variant *treh2-
, colored to *trah2-
, becoming *trā-
▲ Derivatives include thrill, nostril, trench.
Zero-grade form *tr̥(ə)-
1. thrill; nostril from Old English thyr(e)l, thȳrel, a hole (< "a boring through"), from Germanic suffixed form *thur-ila-.
2. Suffixed form *tr̥ə-kwe. thorough, through from Old English thurh, thuruh, through, from Germanic *thurh.
4. Zero-grade form *tr̥ə- and full-grade form *ter(ə)-. avatar from Sanskrit tirati, tarati, he crosses over.
Variant form *trā-
1. trans-, transient, transom from Latin trāns, across, over, beyond, through (perhaps originally the present participle of a verb *trāre, to cross over).
2. Suffixed form *trā-yo-. seraglio, serai; caravansary, lamasery from Iranian *thrāya-, to protect.
Possible extended form *tru-
1. Suffixed form *tru-k-. truculent from Latin trux (stem truc-), savage, fierce, grim (< "overcoming" "powerful" "penetrating").
2. Suffixed nasalized zero-grade form *tru-n-k-o-. tranche, trench, truncate, trunk from Latin truncus, deprived of branches or limbs, mutilated, hence trunk (? < "overcome, maimed").
[Pokorny 5. ter- 1075.]