Merriam-Webster's Collegiate® Dictionary, 11th Edition
BLISTER
I. noun
Etymology: Middle English blister, blester, probably from Old English *blýster, *blǣster; akin to Old Norse blāstr swelling, Old English blǣst blast
Date: 14th century
an elevation of the epidermis containing watery liquid, an enclosed raised spot (as in paint) resembling a blister, an agent (as lewisite) that causes blistering, a fungal disease of plants marked by raised patches on the leaves, any of various structures that bulge out (as a gunner's compartment on a bomber), blistery adjective
II. verb (blistered; blistering)
Date: 15th century
intransitive verb to become affected with a blister, transitive verb to raise a blister on, lambaste 2