locus (n.)youdaoicibaDictYouDict[locus 词源字典]
(plural loci), 1715, "locality," from Latin locus "a place, spot, position," from Old Latin stlocus, literally "where something is placed," from PIE root *st(h)el- "to cause to stand, to place." Used by Latin writers for Greek topos. Mathematical sense by 1750.[locus etymology, locus origin, 英语词源]