Blain (?), n. [OE. blein, bleyn, AS. blgen; akin to Dan. blegn, D. blein; perh. fr. the same root as E. bladder. See Bladder.]
An inflammatory swelling or sore; a bulla, pustule, or blister.
Blotches and blains must all his flesh emboss.
A bladder growing on the root of the tongue of a horse, against the windpipe, and stopping the breath.
© Webster 1913.