Old English dryge, from Proto-Germanic *draugiz (cf. Middle Low German dröge, Middle Dutch druge, Dutch droog, Old High German trucchon, German trocken, Old Norse draugr), from PIE *dreug-.
Meaning "barren" is mid-14c. Of humor or jests, early 15c. (implied in dryly); as "uninteresting, tedious" from 1620s. Of places prohibiting alcoholic drink, 1870 (but dry feast, one at which no liquor is served, is from late 15c.; colloquial dry (n.) "prohibitionist" is 1888, American English). Dry goods (1708) were those measured out in dry, not liquid, measure. Dry land (that not under the sea) is from early 13c. Dry run is from 1940s.