Webster's Revised Unabridged Dictionary · 1913

Dab

Dab (dab) , noun

[Perh. corrupted from adept.]

A skillful hand; a dabster; an expert. [Colloquial]
One excels at a plan or the titlepage, another works away at the body of the book, and the third is a dab at an index. — Goldsmith

Dab , noun

[Perh. so named from its quickness in diving beneath the sand. Compare Dabchick.]

(Zoology) A name given to several species of flounders, esp. to the European species, Pleuronectes limanda. The American rough dab is Hippoglossoides platessoides.

Dab (dab) , intransitive verb

[Old English dabben to strice; akin to OD. dabben to pinch, knead, fumble, dabble, and perh. to German tappen to grope.]

1.
To strike or touch gently, as with a soft or moist substance; to tap; hence, to besmear with a dabber.
A sore should... be wiped... only by dabbing it over with fine lint. — S. Sharp
2.
To strike by a thrust; to hit with a sudden blow or thrust.
To dab him in the neck. — Sir T. More

Dab , noun

1.
A gentle blow with the hand or some soft substance; a sudden blow or hit; a peck.
A scratch of her claw, a dab of her beak. — Hawthorne
2.
A small mass of anything soft or moist.