1. Partitioned-off portion of a larger bound space; a separate section or chamber; the compartments of the limbs are bound deeply by bones and intermuscular septa and superficially by deep fascia and generally are not in communication with the other compartments, and thus infection or increased pathologic pressure may be limited to one compartment; muscles contained within the compartments of the limbs share similar functions and innervation.
2. A separate division; specifically, a structural or biochemical portion of a cell that is separated from the rest of the cell.
3. A chemical or physical subdivision of a system in which the ratio of the concentration of a labeled entity to that of an unlabled entity is constant over a defined period.
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