Definition of "vesicle"

(cytology) A membrane-bound compartment found in a cell.

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.  examples

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.

(anatomy) A pocket of embryonic tissue that is the beginning of an organ.  examples

(geology) A small cavity formed in volcanic rock by entrapment of a gas bubble during solidification.  quotations