tau coefficient of correlation vs Kendall's tau

tau coefficient of correlation and Kendall's tau both are nouns.

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

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

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

Other synonyms of tau coefficient of correlation include Kendall rank correlation.

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