running head vs heading

running head and heading both are nouns.

Word	Noun	Adjective	Verb	Adverb
running head	Yes	No	No	No
heading	Yes	No	No	No

As nouns, heading is a hypernym of running head; that is, heading is a word with a broader meaning than running head:

running head: a heading printed at the top of every page (or every other page) of a book
heading: a line of text serving to indicate what the passage below it is about

Other hypernyms of running head include head, header.

running head (noun)	heading (noun)
a heading printed at the top of every page (or every other page) of a book	a horizontal (or nearly horizontal) passageway in a mine
	a line of text serving to indicate what the passage below it is about
	the direction or path along which something moves or along which it lies