1The quality of being logical, reasonable, or in accordance with reason; rarely used as a standalone noun in modern Japanese and mostly appears in compounds such as 合理的 (rational) and 合理化 (rationalization).
経営陣は感情よりも合理を優先して判断した。
The management prioritized rationality over emotion in making their decision.
合理を追求するあまり、人情味が失われることもある。
In the pursuit of pure rationality, human warmth can sometimes be lost.