Word Origin & History. epicene mid-15c., originally a grammatical term for nouns that may denote either gender, from L. epicoenus common, from Gk. Extended sense of characteristic of both sexes first recorded in English c.1600; that of effeminate 1630s.
A parallelogram is a quadrilateral with two pairs of parallel sides. Equivalent conditions are that opposite sides are of equal length; that opposite angles are equal; or that the diagonals bisect each other. Parallelograms also include the square, rectangle, rhombus and rhomboid. Rectangle: all four angles are right angles. 2  An equivalent condition is that the diagonals bisect each other and are equal in length. 3  Informally: a box or oblong (including a square). 4  Square (regular quadrilateral): all four sides are of equal length (equilateral), and all four angles are right angles.
The Rhombus. A rhombus is a four-sided shape where all sides have equal length. Also opposite sides are parallel and opposite angles are equal. Another interesting thing is that the diagonals (dashed lines in second figure) meet in the middle at a right angle.In other words they bisect (cut in half) each other at right angles.uadrilaterals. Quadrilateral just means four sides. (quad means four, lateral means side). A Quadrilateral has four-sides, it is 2-dimensional (a flat shape), closed (the lines join up), and has straight sides.