Definition:Interval/Ordered Set/Endpoint

Definition
Let $\struct {S, \preccurlyeq}$ be an ordered set.

Let $a, b \in S$.

Let:
 * $\closedint a b$

or
 * $\hointr a b$

or
 * $\hointl a b$

or
 * $\openint a b$

be an interval.

The elements $a, b \in S$ are known as the endpoints (or end points) of the interval.

$a$ is sometimes called the left hand endpoint and $b$ the right hand end point of the interval.

Also known as
The endpoints can also be written as end points.

Also see

 * Definition:Endpoint of Real Interval