Noun, pl. vacuoles
1. A vacuole is a membrane-bound organelle which is present in all plant and fungal cells and some protist, animal and bacterial cells. Vacuoles are essentially enclosed compartments which are filled with water containing inorganic and organic molecules including enzymes in solution, though in certain cases they may contain solids which have been engulfed. Vacuoles are formed by the fusion of multiple membrane vesicles and are effectively just larger forms of these. The organelle has no basic shape or size; its structure varies according to the needs of the cell. (wikipedia.org)
A large membrane-bound vesicle in a cell’s cytoplasm. (wiktionary.com)
3. A membrane-bound vesicle found in the cytoplasm of a cell whose function includes intracellular secretion, excretion, storage, and digestion. (biology-online.org)
4. A space or vesicle within the cytoplasm of a cell, enclosed by a membrane and typically containing fluid. (Google dictionary)
5. A small cavity or space in tissue, esp. in nervous tissue as the result of disease. (Google dictionary)
Word origin: Latin vacuolum, diminutive form of vacuum.