An assisted living facility is a community for seniors who cannot live independently. One of the reasons that assisted living centers are appealing to many people is that they offer a relatively high level of independence.
A line segment is a piece, or part, of a line in geometry. A line segment is represented by end points on each end of the line segment. A line in geometry is represented by a line with arrows at each end.
The geometric definition of a closed line segment: the intersection of all points at or to the right of A with all points at or to the left of B.