This is called a "ray". (It is equal to one half of a line.)
It is called a line segement
line
A line is a straight path that extends infinitely or endlessly in opposite directions. A straight path that joins two points is called a line segment.
a line
It is a ray.
i think i line.
a line
It is a straight line.
The shortest path between two points is called a geodesic. In flat (Euclidean) space it is simply a straight line.
A ray
The shortest path from a starting point to an endpoint regardless of the path taken is called the "optimal path" or "minimum path." This path minimizes the distance, time, or cost required to reach the endpoint.
A ray is a straight path of points that goes on forever in only one direction. A line would go on forever in two directions.