Chapter 7 - Section 7.5 - Vectors: An Algebraic Approach - 7.5 Problem Set - Page 404: 2

The coordinate $a$ is called that horizontal component of $V$ and the $y$ coordinate $b$ is called vertical component of $V$.

If a vector $V$ is in standard position and the tip of the vector corresponds to the point $(a,b)$ then we can write the vector in component from as $ai+bj$.\\ The coordinate $a$ is called that horizontal component of $V$ and the $y$ coordinate $b$ is called vertical component of $V$.