1. A interrupt in the surface of a thing made by scratching, or by rubbing with anything pointed or rough; a slight wound, mark, furrow, or incision. "The coarse file . . . Makes deep scratches in the work." (Moxon) "These nails with scratches deform my breast." (Prior) "God forbid a shallow scratch must drive The prince of Wales from such a field as this." (Shak) 2. A line across the prize ring; up to which boxers are brought when they join fight; hence, test, trial, or proof of courage; as, to bring to the scratch; to come up to the scratch. 3.
Minute, but tender and troublesome, excoriations, covered with scabs, upon the heels of horses which have been used where it is very wet or muddy.
4. A kind of wig covering only a portion of the head.
5. A shot which scores by chance and not as intended by the player; a fluke. Scratch cradle. See Cratch cradle, under Cratch.
Scratch herb, a climbing knotweed (Polygonum sagittatum) with a square stem beset with beautiful recurved prickles along the angles. Scratch wig. Same as Scratch, 4, above.
Source: Websters Vocabulary