rationyoudaoicibaDictYouDict[ration 词源字典]
ration: [18] Ration, like reason, comes from Latin ratiō, a derivative of the verb rērī ‘think, calculate’. This meant, among other things, ‘calculation, computation’, in which sense it has yielded English ratio [17]. In the Middle Ages it was used for an ‘amount of provisions calculated for a soldier’, and that meaning has channelled via Spanish ración and French ration into English as ration.

The ‘thinking’ sense of ratiō has reached English as reason, but its derivative rational [14] is less heavily disguised. Other English descendants of Latin rērī include rate and ratify [14], and the -red of hundred comes from a prehistoric Germanic *rath ‘number’, which came ultimately from Latin ratiō.
=> hundred, rate, ratio, reason[ration etymology, ration origin, 英语词源]
ration (n.)youdaoicibaDictYouDict
1550, "reasoning," later, "relation of one number to another" (1660s), then "fixed allowance of food" (1702, often rations, from French ration in this sense), from Latin rationem (nominative ratio) "a reckoning, calculation, proportion" (see ratio). The military pronunciation (rhymes with fashion) took over from the preferred civilian pronunciation (rhymes with nation) during World War I.
ration (v.)youdaoicibaDictYouDict
"put (someone) on a fixed allowance," 1859, from ration (n.); sense of "apportion in fixed amounts" is from 1870. Related: Rationed; rationing.