vesicle

Etymology

From Middle French vesicule, from Latin vēsīcula.

noun

1. (cytology) A membrane-bound compartment found in a cell.
2. A small bladder-like cell or cavity, as:
   1. (botany) A small sac filled with juice, one of many constituting the pulp of a fruit such as an orange, lemon, or grapefruit.
      Coordinate term: acinus
   2. (biology, medicine) A small sac or cyst or vacuole, especially one containing fluid. A blister formed in or beneath the skin, containing serum. A bleb.
      1. (biology, medicine) (usually and especially) Such a blister that is less than 5 mm in diameter.
         Coordinate term: bulla
3. (anatomy) A pocket of embryonic tissue that is the beginning of an organ.
   Coordinate term: germ
4. (geology) A small cavity formed in volcanic rock by entrapment of a gas bubble during solidification.
   It frequently contains holes, or vesicles, especially nearer the surface of a flow where gas has escaped. 2004, Richard Fortey, The Earth, Folio Society, published 2011, page 51