rectilinear (adj.)youdaoicibaDictYouDict[rectilinear 词源字典]
"forming a straight line," 1650s, with -ar + rectiline (1560s), from Late Latin rectilineus, from rectus "straight" (see right (adj.1)) + linea "line" (see line (n.)). Related: Rectilineal (1640s).[rectilinear etymology, rectilinear origin, 英语词源]