Angle
Geometry shape formed by two rays (initial and ending sides of the angle) that share a common endpoint called the vertex. You may name an angle using the vertex, or a point in each ray and the vertex label in the center.

Isosceles trapezoid
Trapezoid with two non-congruent and non-parallel sides. 

Polygon
It is a closed plane figure with a least three straight segments as sides.

Quadrilateral
A four-sided polygon.

Segment
Line segment; A section of a line, defined by two end points and all the points between them.

Trapezoid
Quadrilateral with exactly one pair of parallel sides.