blister
Pronunciation: /ˈblɪstə/
noun
- 1a small bubble on the skin filled with serum and caused by friction, burning, or other damage: his heels were covered in blisters
- a swelling filled with air or fluid on the surface of a plant, heated metal, painted wood, etc.: check for cracks and blisters in sheet roofing felt
- Medicine, chiefly historical a preparation applied to the skin to form a blister.
verb

Origin:
Middle English: perhaps from Old French blestre 'swelling, pimple'