Wiktionary
coordinate axis
alt. (context mathematics geometry English) One of the lines in the coordinate system that represents one of the dimensions. n. (context mathematics geometry English) One of the lines in the coordinate system that represents one of the dimensions.
WordNet
coordinate axis
n. one of the fixed reference lines of a coordinate system
Usage examples of "coordinate axis".
In other words, that part of space affected by the distortion of the coordinate axis.