ETYM French rationalité, or Latin rationalitas.
1. The quality of being consistent with or based on logic; SYN. rationalness.
2. The state of having good sense and sound judgment; SYN. reason, reasonableness.

ETYM Old Eng. resoun, French raison, from Latin ratio (akin to Goth. rathjô number, account, garathjan to count, German rede speech, reden to speak), from reri, ratus, to reckon, believe, think. Related to Arraign, Rate, Ratio, Ration.
1. A fact that logically justifies some premise or conclusion.
2. A rational motive for a belief or action; SYN. ground.
3. An explanation of the cause of some phenomenon.
4. The capacity for rational thought or inference or discrimination; SYN. understanding, intellect. + prikaži više

ETYM Latin sanitas, from sanus sound, healthy. Related to Sane.
Normal or sound powers of mind; SYN. saneness.