| tan | 1. To convert (the skin of an animal) into leather, as by usual process of steeping it in an infusion of oak or some other bark, whereby it is impregnated with tannin, or tannic acid (which exists in several species of bark), and is thus rendered firm, durable, and in some degree impervious to water. The essential result in tanning is due to the fact that the tannins form, with gelatins and albuminoids, a series of insoluble compounds which constitute leather. Similar results may be produced by the use of other reagents in place of tannin, as alum, and some acids or chlorides, which are employed in certain processes of tanning. 2. To make brown; to imbrown, as by exposure to the rays of the sun; as, to tan the skin. Origin: F. Tanner, LL. Tannare. See Tan. 1. The bark of the oak, and some other trees, bruised and broken by a mill, for tanning hides; so called both before and after it has been used. Called also tan bark. 2. A yellowish-brown colour, like that of tan. 3. A brown colour imparted to the skin by exposure to the sun; as, hands covered with tan. <botany> Tan bed, a bed made of tan; a bark bed. Tan pickle, the liquor used in tanning leather. Tan spud, a spud used in stripping bark for tan from trees. Tan stove. See Bark stove, under Bark. Tan vat, a vat in which hides are steeped in liquor with tan. Origin: F. Tan, perhaps fr. Armor. Tann an oak, oak bar; or of Teutonic origin; cf. G. Tanne a fir, OHG. Tanna a fir, oak, MHG. Tan a forest. Cf. Tawny. Source: Websters Dictionary (01 Mar 1998) |
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| tana | <zoology> Same as Banxring. Source: Websters Dictionary (01 Mar 1998) |
| tanacetol | C10H16O;the chief constituent of cedar leaf oil; a stimulant similar to camphor. Synonym: absinthol, tanacetol, tanacetone, thujol, thuyol, thuyone. (05 Mar 2000) |
| tanager | <ornithology> Any one of numerous species of bright-coloured singing birds belonging to Tanagra, Piranga, and allied genera. The scarlet tanager (Piranga erythromelas) and the summer redbird (Piranga rubra) are common species of the United States. Origin: NL. Tanagra, probably fr. Brazilian tangara. Source: Websters Dictionary (01 Mar 1998) |
| tanagrine | <zoology> Of or pertaining to the tanagers. Source: Websters Dictionary (01 Mar 1998) |
| tanagroid | <zoology> Tanagrine. Origin: Tanager. Source: Websters Dictionary (01 Mar 1998) |
| tanate | <zoology> An Asiatic wild dog (Canis procyonoides), native of Japan and adjacent countries. It has a short, bushy tail. Synonym: raccoon dog. Source: Websters Dictionary (01 Mar 1998) |
| tandem | Term used to describe multiple copies of the same sequence in a polynucleic acid that lie adjacent to one another. (05 Mar 2000) |
| tandem repeat | <molecular biology> Copies of genes repeated one after another along a chromosome: for example the 40S rRNA genes in somatic cells of toads, of which there are about 500 copies. (18 Nov 1997) |
| tandem repeat sequence | <molecular biology> Multiple copies of the same base sequence on a chromosome, used as a marker in physical mapping. (09 Oct 1997) |
| tandem repeat sequences | Multiple copies of the same DNA base sequence on a chromosome; used as a marker in physical mapping of the chromosome. (12 Dec 1998) |
| tang | <botany> A coarse blackish seaweed (Fuscus nodosus). <zoology> Tang sparrow, the rock pipit. Origin: Of Scand. Origin; cf. Dan. Tang seaweed, Sw. Tang, Icel. Thang. Cf. Tangle. Source: Websters Dictionary (01 Mar 1998) |
| tangalung | <zoology> An East Indian civet (Viverra tangalunga). Source: Websters Dictionary (01 Mar 1998) |
| tangent | <geometry> A tangent line curve, or surface; specifically, that portion of the straight line tangent to a curve that is between the point of tangency and a given line, the given line being, for example, the axis of abscissas, or a radius of a circle produced. See Trigonometrical function, under Function. Artificial, or Logarithmic, tangent, the logarithm of the natural tangent of an arc. Natural tangent, a decimal expressing the length of the tangent of an arc, the radius being reckoned unity. <physics> Tangent galvanometer, a form of galvanometer having a circular coil and a short needle, in which the tangent of the angle of deflection of the needle is proportional to the strength of the current. Tangent of an angle, the natural tangent of the arc subtending or measuring the angle. Tangent of an arc, a right line, as ta, touching the arc of a circle at one extremity a, and terminated by a line ct, passing from the center through the other extremity o. Origin: L. Tangens, -entis, p.pr. Of tangere to touch; akin to Gr. Having seized: cf. F. Tangente. Cf. Attain, Contaminate, Contingent, Entire, Tact, Taste, Tax. <geometry> Touching; touching at a single point; specifically meeting a curve or surface at a point and having at that point the same direction as the curve or surface; said of a straight line, curve, or surface; as, a line tangent to a curve; a curve tangent to a surface; tangent surfaces. <geometry> Tangent plane, an endless screw; a worm. Origin: L. Tangens, -entis, p.pr. Source: Websters Dictionary (01 Mar 1998) |
| tangent screen | A flat, usually black surface used to measure the central 30 degrees of the field of vision. Synonym: Bjerrum screen. (05 Mar 2000) |