What is meant by the initial point of a vector?
Geometrically, a vector is a length in a direction.
A vector is (or can be thought of as) a directed line segment.
A vector (unlike a line segment) goes from one point to another.
A line segment has two endpoints and a length. It is a length in a particular location.
A vector has only a length and a direction. But we like to represent vectors using line segments.
When we try to represent a vector using a line segment, we need to distinguish one direction along the segment from the other direction. Part of doing this (or one way of doing it) is to distinguish the two endpoints by labeling one of them "initial" and the other "terminal"
For example, using 2 dimensional coordinates:
There is a line segment connecting the points
There as also a vector from
and a different vector from
The vector from
But it has a different initial point.