blisters

noun

1. 1.A small bubble between the layers of the skin that contains watery or bloody fluid and is caused by friction and pressure, burning, freezing, chemical irritation, disease or infection.
2. 2.A swelling on a plant.
3. 3.Something applied to the skin to raise a blister; a vesicatory or other applied medicine.
4. 4.A bubble, as on a painted surface.
5. 5.(roofing) An enclosed pocket of air, which may be mixed with water or solvent vapor, trapped between impermeable layers of felt or between the membrane and substrate.