15 terms

Square

4 equal sides. 90 degree angles.

Rectangle

quadrilateral. 90 degree angles.

Quadrilateral

4-sided polygon

Triangle

3-sided polygon

parallelogram

4-sided quadrilateral. 2 pairs of parallel lines

trapezoid

4-sided quadrilateral. 1 pair of parallel lines

rhombus

4 equal-sided polygon

polygon

many-sided figure, closed, straight line segment

regular polygon

polygon with congruent sides and congruent angles

irregular polygon

polygon without all congruent sides

pentagon

5-sided polygon

hexagon

6-sided polygon

heptagon

7-sided polygon

octagon

8-sided polygon

nonagon

9-sided polygon