1 having sound judgement; moderate; ready to listen to reason.
2 in accordance with reason; not absurd.
3 a within the limits of reason; not greatly less or more than might be expected. b inexpensive; not extortionate. c tolerable, fair.
4 archaic endowed with the faculty of reason.
Derivatives:
reasonableness n. reasonably adv.
Etymology: ME f. OF raisonable (as REASON) after L rationabilis
Useful english dictionary. 2012.