ratio
n.
1630s, "reason, rationale," from Latin ratio "reckoning, numbering, calculation; business affair, procedure," also "reason, reasoning, judgment, understanding," from rat-, past participle stem of reri "to reckon, calculate," also "think" (see reason, n.). Mathematical sense "relationship between two numbers" is attested from 1650s.
〔李〕[rat;-ion.] n.比，比率； 比例； 系数 ←rat (L reri,ratus)=to think or judge 想，判断