Position

Position is the location of an object relative to a chosen origin and coordinate system.

In one-dimensional motion, position is usually represented by a signed coordinate such as $s$, $x$, or $y$.

Position answers the question: where is the object now?

The number is meaningful only after the origin and positive direction are defined. For example, $s=-4\mathrm{m}$ means the object is $4\mathrm{m}$ on the negative side of the origin. It does not mean the object travelled a negative distance.

In textbook 1.1, $x$ is used for a horizontal coordinate, $y$ for a vertical coordinate, and $s$ for a general coordinate along any straight line.