adj. & n.
--adj.
1. a that can be varied or adapted (a rod of variable length; the pressure is variable). b (of a gear) designed to give varying speeds.
2 apt to vary; not constant; unsteady (a variable mood; variable fortunes).
3 Math. (of a quantity) indeterminate; able to assume different numerical values.
4 (of wind or currents) tending to change direction.
5 Astron. (of a star) periodically varying in brightness.
6 Bot. & Zool. (of a species) including individuals or groups that depart from the type.
7 Biol. (of an organism or part of it) tending to change in structure or function.
--n.
1. a variable thing or quantity.
2 Math. a variable quantity.
3 Naut. a a shifting wind. b (in pl.) the region between the NE and SE trade winds.
Derivatives:
variability n. variableness n. variably adv.
Etymology: ME f. OF f. L variabilis (as VARY)