Acute Angle

Acute Triangle

Adjacent Faces

Adjacent Sides

Adjacent Vertices

Angle

Angle Bisector

Angle in a Plane

Angular Sector

Annulus

Auguste Ferdinand Möbius (1790-1868)

Axis of Revolution

Base of a Geometric Solid

Bipyramid

Boundary

Broken Line

Cabinet Perspective

Cavalier Projection

Central Angle

Central Angle of a Regular Polygon

Centre of a Circle

Centre of a Line Segment

Centre of a Regular Polygon

Cevian

Circle

Circle in a Geometric Plane

Circular Sector

Circular Segment

Circumference of a Circle

Circumference of a Sphere

Circumscribed Circle of a Polygon

Closed Curve

Closed Plane Surface

Concave Polygon

Concave Quadrilateral

Concentric

Cone

Cone of Revolution

Congruent Figures

Congruent Line Segments

Congruent Polygons

Congruent Sides

Congruent Triangles

Conical Perspective

Conical Surface

Conjugate Axis

Contraction

Convex

Convex Polygon

Convex Polyhedron

Convex Quadrilateral

Convex Solid

Coplanar Lines

Corresponding Elements

Corresponding Sides

Cube

Curvature

Curve

Curved line

Cylinder

Cylinder of Revolution

Cylindrical Surface

Decagon

Decahedron

Decomposable Solid

Degree of an Angle

Deltahedron

Deltoid

Diagonal

Diagonal of a Polygon

Diagonal of a Polyhedron

Diameter

Dihedral Angle

Dilation in a Cartesian Plane

Direct Isometry

Directrix

Disphenoid

Dodecagon

Dodecahedron

Edge of a Polygonal Chain

Enneagon

Equiangular

Equiangular Polygon

Equidistant

Equilateral

Equilateral Hyperbola

Equilateral Polygon

Equilateral Triangle

Equipollence

Equivalent

Equivalent Figures

Equivalent Solids

Euler’s Formula

Exterior Angle of a Polygon

Face

Face of a Solid

Fair Die

Figures With Line Symmetry

Figures with Point Symmetry

Fixed Line