noun
- a bag-like structure in a living organism, especially one containing fluid
Usage: biology
Examples
- The air sacs in the lungs help with gas exchange.
- The spider wrapped its prey in a silk sac.
- Each egg was protected in its own amniotic sac.
- The doctor examined the fluid-filled sac near the joint.
- Pollen grains develop within the anther sac.
- The yolk sac provides nutrients to the developing embryo.