From The Collaborative International Dictionary of English v.0.48 [gcide]:
Rationality \Ra`tion*al"i*ty\ (r[a^]sh"[u^]n*[a^]l"[i^]*t[y^];
277), n.; pl. -ties (-t[i^]z). [F. rationalit['e], or L.
rationalitas.]
The quality or state of being rational; agreement with
reason; possession of reason; due exercise of reason;
reasonableness.
[1913 Webster]
When God has made rationality the common portion of
mankind, how came it to be thy inclosure? --Gov. of
Tongue.
[1913 Webster]
Well-directed intentions, whose rationalities will
never bear a rigid examination. --Sir T.
Browne.
[1913 Webster]
From WordNet (r) 3.0 (2006) [wn]:
rationality
n 1: the state of having good sense and sound judgment; "his
rationality may have been impaired"; "he had to rely less
on reason than on rousing their emotions" [syn:
rationality, reason, reasonableness]
2: the quality of being consistent with or based on logic [syn:
rationality, rationalness]