Parallelogram

Part of speech: noun

Pronunciation: /ˌpæ.ɹəˈlɛl.əˌɡɹæm/

Definitions

1. A four-sided figure whose opposite sides are both equal in length and run parallel to each other while also having equal opposite angles A geometric shape defined by having opposite sides that are parallel and equal, with diagonals that bisect each other A quadrilateral where the properties include opposite sides being equal and parallel, along with equal measures of opposite angles
2. A polygon with four sides where each pair of opposite sides are parallel and of equal length
3. A quadrilateral characterized by having both pairs of opposite sides parallel and congruent

Etymology: The Greek mathematicians who named this shape were describing something very literal: a figure whose opposite sides run alongside each other. The name joins "parállēlos", meaning "parallel" or literally "beside one another", with "grammḗ", meaning "line", so the whole term is a description of a figure bounded by lines that sit side by side. The Greek compound passed into Latin as "parallelogrammum" and then into English, where it kept the same sense of a four-sided figure built from paired parallel lines. Its ancestry is worth noticing: the "gram" in the word is the same element found in "diagram" and "telegram", where it signals something drawn or written, so a parallelogram is, at root, a drawn line-figure of parallel sides.