bold face vs font

bold face and font both are nouns.

Word	Noun	Adjective	Verb	Adverb
bold face	Yes	No	No	No
font	Yes	No	No	No

As nouns, font is a hypernym of bold face; that is, font is a word with a broader meaning than bold face:

Other hypernyms of bold face include case, face, fount, typeface.

bold face (noun)	font (noun)
a typeface with thick heavy lines	bowl for baptismal water
	a specific size and style of type within a type family