An Etymological Dictionary of Astronomy and Astrophysics

A four-sided → polygon whose opposite sides are parallel. A parallelogram all of whose angles are right angles is a → rectangle.

Etymology (EN): From Fr. parallélogramme, from L. parallelogrammum, from Gk. parallelogrammon “bounded by parallel lines,” from parallelos, → parallel, + gramme “line,” related to graphein “to write, draw” → -graph.

Etymology (PE): Parâsubar, from parâsu, → parallel, + bar, → side.