Four; having four parts; square.
Latin quadrans, a quarter, from quattuor, four.
Examples are quadrilateral, a shape or figure having four sides; quadruped, an animal with four legs; and quadruple, fourfold or having four parts; a quadrangle, a square or rectangular space, so called because it has four angles. The related Latin word for forty, quadraginta, appears in the archaic quadragesimal, a period of forty days (as in the Lenten fast, hence Quadragesima, the first Sunday in Lent) and in quadragenarian, a person aged between 40 and 49. For quadrillion see the entry Number words.