Co-ordinate and Polar coordinate

Co-ordinate noun - A number that identifies a position relative to an axis.

Polar coordinate and co-ordinate are semantically related. In some cases you can replace phrase "Polar coordinate" with "Co-ordinate", this phrases are similar.

Polar coordinate noun - Either of two values that locate a point on a plane by its distance from a fixed pole and its angle from a fixed line passing through the pole.

Co-ordinate and polar coordinate are semantically related. You can use "Co-ordinate" instead a noun phrase "Polar coordinate".