Blister
Blister turns up in 2 fields: waterproofing, production. Here is what it means to the people in each one.
Blister in waterproofing
A raised, trapped pocket of air or moisture vapor within a roof membrane.
A localized swelling in a built-up or modified bitumen roof caused by trapped air, moisture, or solvent vapor expanding under solar heat. Blisters form between membrane plies or between the membrane and the substrate, gradually growing in size and eventually compromising the waterproofing if they rupture.
"Don't step on that blister near the drain, the membrane is stretched thin and might pop."
Blister in production
A thermoformed plastic cavity used to house a product in retail packaging.
A pre-formed plastic shell that holds a small consumer good or pharmaceutical pill, usually sealed to a printed paperboard or foil backing. In manufacturing, these are created on high-speed thermoforming machines that heat a plastic sheet and draw it into a mold cavity. The sealing process requires precise control of heat, pressure, and dwell time.
"The sealer is running too hot and melting the edge of the blister on the new battery packs."