Kendall's tau vs Kendall rank correlation

Kendall's tau and Kendall rank correlation both are nouns.

Word	Noun	Adjective	Verb	Adverb
Kendall's tau	Yes	No	No	No
Kendall rank correlation	Yes	No	No	No

As nouns, Kendall's tau and Kendall rank correlation are synonyms defined as:

Kendall's tau and Kendall rank correlation: a nonparametric measure of the agreement between two rankings

Other synonyms of Kendall's tau include tau coefficient of correlation.

Kendall's tau (noun)	Kendall rank correlation (noun)
a nonparametric measure of the agreement between two rankings	a nonparametric measure of the agreement between two rankings