c.1300, dabben "to strike," of unknown origin, perhaps imitative. Modern sense of "strike with a slight, quick pressure" developed by mid-16c., influenced by French dauber (see daub). Related: Dabbed; dabbing. As a noun from c.1300, "heavy blow with a weapon." Dab hand is British slang, 1828, from dab "expert" (1690s), said to be school slang, of unknown origin, perhaps from dab in the "strike lightly" sense.
An expert; a skilled person; an adept: He is reportedly a dab hand at setting lofty prices
[1828+ British; fr late 1600s dab, ''an expert,'' of unknown origin]
any of the flatfishes of the genus Limanda, family Pleuronectidae, found in the North Atlantic and North Pacific. Dabs are right-eyed flatfish-i.e., the eyes are usually on the right side of the head. The dab of European waters is L. limanda, an abundant and valuable food fish. It is small, usually under 25 cm (10 inches) long, and light brown, with or without dark spots.