A coordinate is the position of an object in a coordinate system relative to the corresponding axis. Coordinates are often seen together with other coordinates, which can describe the position of an object in a coordinate system with one, two, three, or even more dimensions.

In One Dimension

In a one-dimensional coordinate system, which is the same as a number line, only one number is used to indicate the position of a point on that line.

In Two Dimensions

In a two-dimensional coordinate system, points are usually expressed as a coordinate pair — also called an ordered pair — denoted by $(x,y).$ The first coordinate states the position along the $x\text{-}$axis and the second coordinate states the position along the $y\text{-}$axis.

In Three Dimensions

In a three-dimensional coordinate system, three numbers are needed to express a coordinate position. It is referred to as an ordered triple denoted by $(x,y,z).$ Each number states the position of the point relative to its corresponding axes.

More Than Three Dimensions

Although a coordinate system with more than three coordinates cannot be easily represented graphically, it is possible to work with its points by using their coordinates. In such cases, the points will have as many coordinates as the system has. In an $n\text{-}$dimensional system, the points are called ordered tuples, or $n\text{-}$tuples, and they are denoted as $(a_1,a_2,\dots ,a_n).$