Coordinates are a set of values that show an exact position.
On maps and graphs it is common to have a pair of numbers to show where a point is: the first number shows the distance along and the second number shows the distance up or down.
Example: the point (12,5) is 12 units along, and 5 units up.
But there are other types of coordinates, such as polar coordinates and 3 dimensional coordinates.
See: Polar Coordinates