bulge vs nub

bulge and nub both are nouns.

Word	Noun	Adjective	Verb	Adverb
bulge	Yes	No	Yes	No
nub	Yes	No	No	No

As nouns, nub is a hyponym of bulge; that is, nub is a word with a more specific, narrower meaning than bulge:

bulge: something that bulges out or is protuberant or projects from its surroundings
nub: a small lump or protuberance

Other hyponyms of bulge include frontal eminence, occipital protuberance, belly, caput, mogul, nubble, snag, wart.

bulge (noun)	nub (noun)
something that bulges out or is protuberant or projects from its surroundings	the choicest or most essential or most vital part of some idea or experience
	a small piece
	a small lump or protuberance

bulge (verb)	nub (verb)
swell or protrude outwards
cause to bulge or swell outwards
bulge outward
bulge out; form a bulge outward, or be so full as to appear to bulge