*blister*

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. [ 1913 Webster ]

And painful blisters swelled my tender hands. Grainger. [ 1913 Webster ]

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. [ 1913 Webster ]

3. A vesicatory; a plaster of Spanish flies, or other matter, applied to raise a blister. Dunglison. [ 1913 Webster ]

Blister beetle, a beetle used to raise blisters, esp. the Lytta vesicatoria (or Cantharis 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. [ 1913 Webster ]