1. To treat as a physician; cure; heal. 2. To bleed by the use of leeches. 3. Any of numerous carnivorous or bloodsucking annelid worms that comprise the class Hirudinea, that typically have a flattened segmented lance-shaped body with well-marked external annulations, a sucker at each end, a mouth within the anterior sucker, and a large stomach with pouches of large capacity at the sides, that are hermaphroditic usually with direct development, and that occur chiefly in freshwater although a few are marine and some tropical forms are terrestrial.