fulcrum (n.)youdaoicibaDictYouDict[fulcrum 词源字典]
in mechanics, "a prop, a support" (on which a lever turns), 1670s, from Latin fulcrum "bedpost, foot of a couch," from fulcire "to prop up, support" (see balk (n.)).[fulcrum etymology, fulcrum origin, 英语词源]