Thin, v. i. To grow or become thin; -- used with some adverbs, as out, away, etc.; as, geological strata thin out, i. e., gradually diminish in thickness until they disappear.

Thin, v. t. [imp. & p. p. Thinned (?); p. pr. & vb. n. Thinning.] [Cf. AS. geþynnian.] To make thin (in any of the senses of the adjective).

Thin, adv. Not thickly or closely; in a seattered state; as, seed sown thin.

Spain is thin sown of people.

Thin (?), a. [Compar. Thiner (?); superl. Thinest.] [OE. thinne, thenne, thunne, AS. þynne; akin to D. dun, G. dünn, OHG. dunni, Icel. þunnr, Sw. tunn, Dan. tynd, Gael. & Ir. tana, W. teneu, L. tenuis, Gr. ? (in comp.) stretched out, ? stretched, stretched out, long, Skr. tanu thin, slender; also to AS. ?enian to extend, G. dehnen, Icel. ?enja, Goth. ?anjan (in comp.), L. tendere to stretch, tenere to hold, Gr. ? to stretch, Skr. tan. √51 & 237. Cf. Attenuate, Dance, Tempt, Tenable, Tend to move, Tenous, Thunder, Tone.] 1. Having little thickness or extent from one surface to its opposite; as, a thin plate of metal; thin paper; a thin board; a thin covering.

2. Rare; not dense or thick; -- applied to fluids or soft mixtures; as, thin blood; thin broth; thin air. Shak.

In the day, when the air is more thin.

Satan, bowing low
His gray dissimulation, disappeared,
Into thin air diffused.

3. Not close; not crowded; not filling the space; not having the individuals of which the thing is composed in a close or compact state; hence, not abundant; as, the trees of a forest are thin; the corn or grass is thin.

Ferrara is very large, but extremely thin of people.

4. Not full or well grown; wanting in plumpness.

Seven thin ears . . . blasted with the east wind.
Gen. xli. 6.

5. Not stout; slim; slender; lean; gaunt; as, a person becomes thin by disease.

6. Wanting in body or volume; small; feeble; not full.

Thin, hollow sounds, and lamentable screams.

7. Slight; small; slender; flimsy; wanting substance or depth or force; superficial; inadequate; not sufficient for a covering; as, a thin disguise.

My tale is done, for my wit is but thin.

Thin is used in the formation of compounds which are mostly self-explaining; as, thin-faced, thin-lipped, thin-peopled, thin-shelled, and the like.

Thin section. See under Section.