the measure of a straight-line distance between two points is called length.
A straight line is the shortest distance between two points, a line is the delineation of a connection between two or more points.
The shortest distance between two points is... a straight line.
a straight line
The length of a straight line between those two points.
The shortest distance between four points is a straight line to and from each individual point. If all four points are aligned, the result will be a single straight line through all four points.
Two points in a plane.
displacement
displacement
It has been said that a straight line is the shortest distance between two points.
That's called the "distance" between the points.
An interval. The short distance is the length of a straight line joining the two points.