Ear
A Principal Vertex 
of a Simple Polygon 
is called an ear if the diagonal 
that bridges lies entirely in . Two ears and 
are said to overlap if
The Two-Ears Theorem states that, except for Triangles, every Simple Polygonhas at least two nonoverlapping ears.See also Anthropomorphic Polygon, Mouth, Two-Ears Theorem
References
Meisters, G. H. ``Polygons Have Ears.'' Amer. Math. Monthly 82, 648-751, 1975. Meisters, G. H. ``Principal Vertices, Exposed Points, and Ears.'' Amer. Math. Monthly 87, 284-285, 1980. Toussaint, G. ``Anthropomorphic Polygons.'' Amer. Math. Monthly 122, 31-35, 1991.
- Tangent Hyperbolas Method
- Tangential Angle
- Tangential Triangle
- Tangential Triangle Circumcenter
- Tangent Indicatrix
- Tangent Line
- Tangent Map
- Tangent Number
- Tangent Plane
- Tangents Law
- Tangent Space
- Tangent Vector
- Tangle
- Tanglecube
- Tangled Hierarchy
- Tangram
- Tanh
- Taniyama Conjecture
- Taniyama-Shimura Conjecture
- Tank
- Tantrix
- Tapering Function
- Tarry-Escott Problem
- Tarry Point
- Tarski's Theorem