If you know what the quadrilaterals look like, their definitions should make sense and be pretty easy to understand (though the kite definition is a bit of a mouthful). Here are the seven quadrilaterals:

Kite: A quadrilateral in which two disjoint pairs of consecutive sides are congruent (“disjoint pairs” means that one side can’t be used in both pairs)

Parallelogram: A quadrilateral that has two pairs of parallel sides

Rhombus: A quadrilateral with four congruent sides; a rhombus is both a kite and a parallelogram

Rectangle: A quadrilateral with four right angles; a rectangle is a type of parallelogram

Square: A quadrilateral with four congruent sides and four right angles; a square is both a rhombus and a rectangle

Trapezoid: A quadrilateral with exactly one pair of parallel sides (the parallel sides are called bases)

Isosceles trapezoid: A trapezoid in which the nonparallel sides (the legs) are congruent