bulge vs nubble

bulge and nubble both are nouns.

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

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

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

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

bulge (noun)	nubble (noun)
something that bulges out or is protuberant or projects from its surroundings	a small lump or protuberance

bulge (verb)	nubble (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