(grammar) A grammatical number referring to four (more) things.
(mathematics) A set of points with all the combinatorial properties of a quadric (a quadric being the set of points of PG(n, q) whose coordinates satisfy a quadradic equation).
(in discussions of the rhythm of written works)
(grammar) Referring to four (more) things; of, in or relating to the quadral grammatical number.
Origin of quadral
From New Latin quadralis, from quadru- (“four-”) + -alis