Vesicle (noun)

A small blister or sac containing fluid, as found in the skin or on an organ.

Origin:

Late 18th century: from latin vesicula "small bladder", diminutive of vesica "bladder, blister". .

Examples:

1. The vesicle on the skin contained a clear fluid.
2. The vesicle was caused by a viral infection.
3. The vesicles on the plant's leaves were filled with sap.
4. The vesicle ruptured and released its contents.
5. The vesicles were a symptom of a rare disease.