Definitions

Term	Description
Ray	Directed line segment consisting of an endpoint and a direction. Notated as `\overrightarrow{EF}`, where `E` denotes the endpoint and `F` denotes a point along the ray.
Angle	Union of two rays with a common endpoint. Notated as `\angle DEF` or `\angle FED`, where `D` and `F` are along the points of each ray, and `E` is the vertex. `\angle EFD` is not valid notation, because the vertex must be the middle.