I. |kwädrə|lad.ərəl, -atərəl, -a.trəl sometimes |kwȯd- adjective
Etymology: probably from (assumed) New Latin quadrilateralis, from Latin quadrilaterus quadrilateral (from quadri- + later-, latus side) + -alis -al — more at lateral
1. : having four sides — used especially of a plane figure
2. : shared by four parties
quadrilateral control by foreign powers
II. noun
( -s )
1. : a plane figure of four sides and consequently four angles : a quadrangular figure : a plane figure formed by four lines — see complete quadrilateral
2. : something resembling or suggesting a quadrilateral ; specifically : an area defended by four fortresses supporting each other