Blis″ter (�), n. [OE.; akin to OD. bluyster, fr. the same root as blast, bladder, blow. See Blow to eject wind.] 1. A vesicle of the skin, containing watery matter or serum, whether occasioned by a burn or other injury, or by a vesicatory; a collection of serous fluid causing a bladderlike elevation of the cuticle.
And painful blisters swelled my tender hands.
Grainger.
2. Any elevation made by the separation of the film or skin, as on plants; or by the swelling of the substance at the surface, as on steel.
3. A vesicatory; a plaster of Spanish flies, or other matter, applied to raise a blister. Dunglison.
Blister beetle, a beetle used to raise blisters, esp. the Lytta (orCantharis) vesicatoria, called Cantharis or Spanish fly by druggists. See Cantharis. — Blister fly, a blister beetle. — Blister plaster, a plaster designed to raise a blister; — usually made of Spanish flies. — Blister steel, crude steel formed from wrought iron by cementation; — so called because of its blistered surface. Called also blistered steel. — Blood blister. See under Blood.