(1) Irritability; the ability to receive and respond to a stimulus.
(2) The ability of the cell or tissue to generate and sometimes propagate action potentials.
(general) The state or a measure of being excitable.
In physiology, the muscle cells, neurons, and endocrine cells are some of the cells with this ability.
Word origin: Latin excitābilis
Related forms: excitable (adjective), excite (verb).
See also: action potential