ERA vs touchstone

ERA and touchstone both are nouns.

Word	Noun	Adjective	Verb	Adverb
ERA	Yes	No	No	No
touchstone	Yes	No	No	No

As nouns, touchstone is a hypernym of ERA; that is, touchstone is a word with a broader meaning than ERA:

ERA: (baseball) a measure of a pitcher's effectiveness; calculated as the average number of earned runs allowed by the pitcher for every nine innings pitched
touchstone: a basis for comparison; a reference point against which other things can be evaluated

Other hypernyms of ERA include criterion, measure, standard.

ERA (noun)	touchstone (noun)
(baseball) a measure of a pitcher's effectiveness; calculated as the average number of earned runs allowed by the pitcher for every nine innings pitched	a basis for comparison; a reference point against which other things can be evaluated