centre of curvature vs center of curvature

centre of curvature and center of curvature both are nouns.

Word	Noun	Adjective	Verb	Adverb
centre of curvature	Yes	No	No	No
center of curvature	Yes	No	No	No

As nouns, centre of curvature and center of curvature are synonyms defined as:

centre of curvature and center of curvature: the center of the circle of curvature

centre of curvature (noun)	center of curvature (noun)
the center of the circle of curvature	the center of the circle of curvature