ことわり 
[] to work jade () put in order () natural law () logic () reason
                                                         
(n) (1) reason, principle, logic, (2) (Buddh) general principle (as opposed to individual concrete phenomenon), (3) (in neo-Confucianism) the underlying principles of the cosmos
りか (n,adj-no) science
りかい (n,vs) understanding, comprehension, appreciation, sympathy
りがく (n) (1) physical science (e.g. chemistry, biology, etc.), (2) physics, (3) lixue (Song-era Chinese philosophy), (4) (arch) philosophy
りがくぶ (n) department of science
りくつ (n) theory, reason
りけい (n) science
りこう (n) science and technology
りこうがくぶ (n) department of science and engineering
りじ (n) director, board of directors
りせい (n) reason, sense
りそう (n,adj-no) ideal, dream
りそうてき (adj-na) ideal
りねん (n) idea
りはつ (n,vs,adj-no) haircut
りふじん (adj-na,n) unreasonable, irrational
りゆう (n) reason, pretext, motive
りろん (n) theory

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Etymologies: 中文字譜 : 説文解字