Meaning

noun an equation in which the highest power of an unknown quantity is a square

noun a polynomial of the second degree

adjective of or relating to or resembling a square

originFrom French quadratique (1765), from Latin quadrātus + -ique (English -ic), form of quadrō (“to make square”), from quādrus (“square”), ultimately from Proto-Indo-European *kʷetwóres (“four”), whence also Latin quartus (“fourth”).

Etymology from Wiktionary, CC BY-SA 3.0