Noah Webster's New International Dictionary of the English Language

1. (superl.) 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. (superl.) Rare; not dense or thick; -- applied to fluids or soft mixtures; as, thin blood; thin broth; thin air.

3. (superl.) 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.

4. (superl.) Not full or well grown; wanting in plumpness.

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

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

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

8. (adv.) Not thickly or closely; in a scattered state; as, seed sown thin.

9. (v. t.) To make thin (in any of the senses of the adjective).

10. (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.