tap dancing vs step dancing

tap dancing and step dancing both are nouns.

Word	Noun	Adjective	Verb	Adverb
tap dancing	Yes	No	No	No
step dancing	Yes	No	No	No

As nouns, step dancing is a hypernym of tap dancing; that is, step dancing is a word with a broader meaning than tap dancing:

tap dancing: a dance step tapped out audibly with the feet
step dancing: dancing in which the steps are more important than gestures or postures

Other hypernyms of tap dancing include hoofing.

tap dancing (noun)	step dancing (noun)
a dance step tapped out audibly with the feet	dancing in which the steps are more important than gestures or postures