One of four fluid-filled cavities in the brain, that are continuous with the central canal of the spinal cord.
One of two lower chambers of the heart.
A membrane-bound compartment found in a cell.
A small sac or cyst or vacuole, especially one containing fluid. A blister formed in or beneath the skin, containing serum. A bleb.
(usually and especially) Such a blister that is less than 5 mm in diameter.
A small cavity formed in volcanic rock by entrapment of a gas bubble during solidification.
A small sac filled with juice, one of many constituting the pulp of a fruit such as an orange, lemon, or grapefruit.
A pocket of embryonic tissue that is the beginning of an organ.