quadrilateral (n.)youdaoicibaDictYouDict[quadrilateral 词源字典]
"four-sided," 1640s, with -al (1) + Latin quadrilaterus, from quadri- "four" (see quadri-) + latus (genitive lateris) "side" (see oblate (n.)). As an adjective from 1650s. Related: Quadrilaterally.[quadrilateral etymology, quadrilateral origin, 英语词源]