curvilinear (adj.)youdaoicibaDictYouDict[curvilinear 词源字典]
1710, from curvi-, comb. form of Latin curvus (see curve (v.)) + linearis, from linea "line" (see line (n.)). Earlier was curvilineal (1650s).[curvilinear etymology, curvilinear origin, 英语词源]