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. variability n. variableness n. variably adv.
[ ME f. OF f. L variabilis (as VARY) ]