Old English bledan "to let blood," in Middle English and after, "to let blood from surgically;" also "to emit blood," from Proto-Germanic *blodjan "emit blood" (cognates: Old Norse blæða, German bluten), from *bhlo-to- "swell, gush, spurt" (see blood, n.). Meaning "extort money from" is from 1670s. Of dyes or paints, from 1862. Related: Bled; bleeding.