Children with expressive language disorder have difficulty conveying or expressing information in speech, writing, sign language or gesture. (For preschool children, the difficulty expressing themselves in writing is not evident, as they have not started formal education.)
A rectangle is defined as a parallelogram (a quadrilateral with two sets of parallel sides) with the non-parallel sides joining perpendicularly (at 90Â°). A square is a rectangle with the additional constraint the all four sides be of equal length.
Noun. 1. rectangle-a parallelogram with four right angles. foursquare, square - (geometry) a plane rectangle with four equal sides and four right angles; a four-sided regular polygon; you can compute the area of a square if you know the length of its sides.