Membrane-Bound Sac in a Cell; Small Tissue Cavity
Puzzle 8 of The 1950s Hard Pack
Question is: Membrane-Bound Sac in a Cell; Small Tissue Cavity
and the answer is: VACUOLE
Word Meaning:
VACUOLE — (cytology) A large membrane-bound vesicle in a cell's cytoplasm.
Definitions from Wiktionary.