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.
All quadrilaterals have 4 sides. A square has got 4 sides of equal length and 4 right angles (right angle = 90 degrees). A Rhombus has got 4 sides of equal length and opposite sides are parallel and angles are equal. The rectangle (oblong) contains 4 right angles (an angle of 90Ë).quare. A square has got 4 sides of equal length and 4 right angles (right angle = 90 degrees). Since ALL the angles in a quadrilateral add up to 360 then 360 divided by 4 must be 90.