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Pronunciation: kap′sūl


  1. A membranous anatomic structure, usually dense, irregular, collagenous connective tissue, which envelops an organ, a joint, or any other part resembling a capsule or envelope.
  2. A fibrous tissue layer enveloping an organ or a tumor, especially if benign.
  3. A solid dosage form in which a drug is enclosed in a hard or soft soluble container or “shell” of a suitable form of gelatin.
  4. A hyaline polysaccharide coating around a fungal or bacterial cell. Bacteria may also have a polypeptide capsule or a slime layer around the cell.

Synonym(s): capsulaTA

[L. capsula, dim. of capsa, box]

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© Copyright 2018 Wolters Kluwer. All Rights Reserved. Review Date: Sep 19, 2016.