From Longman Dictionary of Contemporary Englishparallelogrampar‧al‧lel‧o‧gram /ˌpærəˈleləɡræm/ noun [countable] HMCFa flat shape with four sides in which each side is the same length as the side opposite it and parallel to it → rectangle
Examples from the Corpus
parallelogram• A hexagon, a cube; here comes a parallelogram.• Its profile was an irregular parallelogram, and it appeared to be made up of interlocking blocks of crystalline metal.• It is the envelope of a series of parallelograms of equal area and sharing two sides. 