| trachymedusae | <zoology> A division of acalephs in which the development is direct from the eggs, without a hydroid stage. Some of the species are parasitic on other medusae. Origin: NL, fr.Gr. Rough + medusa. Source: Websters Dictionary (01 Mar 1998) |
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| trachyonychia | Rough-surfaced nails. Origin: G. Trachys, rough, + onyx, onychos, nail, + suffix -ia, condition (05 Mar 2000) |
| trachyphonia | Roughness of voice. Origin: G. Trachys, rough, + phone, voice (05 Mar 2000) |
| trachyspermous | <botany> Rough-seeded. Origin: Gr. Rough + seed. Source: Websters Dictionary (01 Mar 1998) |
| trachystomata | <zoology> An order of tailed aquatic amphibians, including Siren and Pseudobranchus. They have anterior legs only, are eel-like in form, and have no teeth except a small patch on the palate. The external gills are persistent through life. Origin: NL,fr.Gr. Rough + stoma. Source: Websters Dictionary (01 Mar 1998) |
| trachyte | <geology> An igneous rock,usually light gray in colour and breaking with a rough surface. It consists chiefly of orthoclase feldspar with sometimes hornblende and mica. Origin: Gr. Rough, rugged: cg. F. Trachyte. Source: Websters Dictionary (01 Mar 1998) |
| trachytoid | <chemical> Resembling trachyte; used to define the structure of certain rocks. Origin: Trachyte. Source: Websters Dictionary (01 Mar 1998) |
| tracing | 1. Any graphic display of electrical or mechanical cardiovascular events, e.g., electrocardiogram, phlebogram. See: curve. 2. In dentistry, a line or lines, scribed on a table or plate by a pointed instrument, representing a record of movements of the mandible; may be extraoral (made outside the oral cavity) or intraoral (made within the oral cavity). (05 Mar 2000) |
| tracing (cephalometric) | <dentistry> An overlay drawing traced over a cephalometric X-ray that shows specific structures and landmarks that provided a basis for orthodontic therapy. (05 Mar 2000) |
| track | To follow the tracks or traces of; to pursue by following the marks of the feet; to trace; to trail; as, to track a deer in the snow. "It was often found impossible to track the robbers to their retreats among the hills and morasses." (Macaulay) 2. To draw along continuously, as a vessel, by a line, men or animals on shore being the motive power; to tow. Origin: tracked; tracking. 1. A mark left by something that has passed along; as, the track, or wake, of a ship; the track of a meteor; the track of a sled or a wheel. "The bright track of his fiery car." (Shak) 2. A mark or impression left by the foot, either of man or beast; trace; vestige; footprint. "Far from track of men." (Milton) 3. <zoology> The entire lower surface of the foot;-said of birds, ect. 4. A road; a beaten path. "Behold Torquatus the same track pursue." (Dryden) 5. Course; way; as, the track of a comet. 6. A path or course laid out for a race, for exercise, ect. 7. The permanent way; the rails. 8. [Perhaps a mistake for tract] A tract or area, as of land. "Small tracks of ground." Track scale, a railway scale. See Railway. Origin: OF.trac track of horses, mules, trace of animals; of Teutonic origin; cf.D.trek a drawing, trekken to draw, travel, march, MHG. Trechen, pret. Trach. Cf. Trick. Source: Websters Dictionary (01 Mar 1998) |
| track and field | Sports performed on a track, field, or arena and including running events and other competitions, such as the pole vault, shot put, etc. (12 Dec 1998) |
| tracker | 1. One who, or that which, tracks or pursues, as a man or dog that follows game. "And of the trackers of the deer Scarce half the lessening pack was near." (Sir W. Scott) 2. In the organ, a light strip of wood connecting (in path) a key and a pallet, to communicate motion by pulling. Source: Websters Dictionary (01 Mar 1998) |
| tract | <anatomy> A region, principally one of some length, specifically a collection or bundle of nerve fibres having the same origin, function and termination (tractus) or a number of organs, arranged in series, subserving a common function. Origin: L. Tractus (18 Nov 1997) |
| tract of Goll | gracile fasciculus |
| tract of Munzer and Wiener | A fibre bundle arising in the superior colliculus, passing caudoventrally on the same side along the medial side of the lateral lemniscus, issuing fibres terminating in the lateral zone of the mesencephalic tegmentum, and ending in the lateral part of the gray matter of the ventral part of the pons. Synonym: tract of Munzer and Wiener, tractus tectopontinus. (05 Mar 2000) |