The Cartesian coordinates of a point in $\mathbb{R}^{3}$ for determining its place in three-dimensional space are the three real numbers $x$, $y$ and $z$, which are called

• $x$-coordinate or abscissa,

• $y$-coordinate or ordinate,

• $z$-coordinate or applicate.

The last name “applicate” is rare in English, but its equivalents in continental European languages, as “die Applikate” in German and “aplikaat” in Estonian, are more known.

Similarly, in $\mathbb{R}^{n}$ for all  $n=1,\,2,\,3,\,\ldots$  one needs $n$ coordinates for specifying the location of a point.