Acute angle: an angle that measures greater than 0 and less than 90 degrees.

Acute triangle: a triangle that has three acute angles.

Equilateral: a figure that has all sides congruent.

Hexagon: a six-sided polygon.

Irregular polygon: a polygon that has sides of different lengths.

Isosceles: a triangle that has at least two congruent sides.

Nonagon: a polygon that has nine sides.

Obtuse angle: an angle greater than 90 degrees and less than 180 degrees.

Obtuse triangle: a triangle that has an obtuse angle.

Parallelogram: a quadrilateral with opposite sides parallel and equal

Parallel lines: lines that lie in the same plane, but do not intersect.

Polygon: a closed plane (flat, two-dimensional) figure bounded by straight lines; polygons may be regular or irregular. Poly=many Gon=angle

Polyhedron: a three-dimensional solid made up of plane faces. Poly=many Hedron=faces

Perpendicular lines: lines that form right angles where they intersect.

Prism: a polyhedron (geometric solid) with two parallel, same-size bases joined by 3 or more parallelogram-shaped sides.

Quadrilateral: polygon with four sides

Rectangle: parallelogram with all right angles (rectus = right)

Rectangular prism: prism with parallel rectangular faces, a column.

Regular polygon: a polygon that has all sides congruent.

Right angle: an angle that measures 90 degrees.

Right triangle: a triangle that has a right angle.

Scalene triangle: a triangle with sides of different lengths

Tetrahedron: polyhedron with four faces (tetra=four, hedron=face).

Trapezoid: quadrilateral with only two parallel sides

Abstract art/abstraction: Art that contains no recognizable pictorial imagery and uses the elements of art (line, color, shape, form, texture) to communicate.

Architect: The person who designs buildings and oversees their construction.

Architecture: The built environment, the art and science of producing buildings and other structures.

Asymmetry: Without symmetry; not evenly balanced on both sides of a dividing line.

Conceptual art: The idea or concept behind a work of art is the most important element in conceptual art. The artist's concept generates the resulting product, and the work of art is often executed by studio assistants.

Minimalism: A style of art, originating in the 1960s, known for its use of simple geometric forms and industrial materials to create large-scale works. It was often characterized as austere and impersonal, with the cool regularity of a machine.

Neoclassical architecture: Buildings and structures that use design elements from ancient Greek and Roman sources.

Symmetry: Correspondence or mirror reflection in size, shape, and position on opposite sides of a dividing line.

Three-dimensional art: Art that occupies space; sculpture and architecture.

Two-dimensional art: Flat art like drawings, paintings, and photographs.

Ziggurat: An ancient Mesopotamian pyramid-style structure with stepped-back faces or sides.