Entries linking to dryly
Middle English drie "without moisture, comparatively free from water or fluid," from Old English dryge, from Proto-Germanic *draugiz (source also of Middle Low German dröge, Middle Dutch druge, Dutch droog, Old High German trucchon, German trocken, Old Norse draugr), from Germanic root *dreug- "dry."
Meaning "barren" is mid-14c. Of persons, "showing no emotion," c. 1200; of humor or jests, "without show of pleasantry, caustic, sarcastic" early 15c. (implied in dryly). Sense of "uninteresting, tedious" is from 1620s. Of wines, brandy, etc., "free from sweetness or fruity flavor," 1700. Of places prohibiting alcoholic drink, 1870 (dry feast, one at which no liquor is served, is from late 15c.); colloquial dry (n.) "prohibitionist" is by 1888, American English political slang.
Dry goods (1650s) were those dispensed in dry, not liquid, measure. Dry land (that not under the sea) is from early 13c. Dry-nurse "nurse who attends and feeds a child but does not suckle it" is from 1590s. Dry run "rehearsal" is by 1941. Dry ice "solid carbon dioxide" is by 1925.
common adverbial suffix, forming from adjectives adverbs signifying "in a manner denoted by" the adjective, Middle English, from Old English -lice, from Proto-Germanic *-liko- (cognates: Old Frisian -like, Old Saxon -liko, Dutch -lijk, Old High German -licho, German -lich, Old Norse -liga, Gothic -leiko); see -ly (1). Cognate with lich, and identical with like (adj.).
Weekley notes as "curious" that Germanic uses a word essentially meaning "body" for the adverbial formation, while Romanic uses one meaning "mind" (as in French constamment from Latin constanti mente). The modern English form emerged in late Middle English, probably from influence of Old Norse -liga.