consistency (n.)youdaoicibaDictYouDict[consistency 词源字典]
1590s, "firmness of matter," from Medieval Latin consistentia or directly from Latin consistentem, from consistere (see consist). Meaning "state of being in agreement or harmony" (with something) is from 1650s; meaning "self-consistent" is from 1716.[consistency etymology, consistency origin, 英语词源]