node vs nodule

node and nodule both are nouns.

Word	Noun	Adjective	Verb	Adverb
node	Yes	No	No	No
nodule	Yes	No	No	No

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

node (noun)	nodule (noun)
(computer science) any computer that is hooked up to a computer network	a small node
any bulge or swelling of an anatomical structure or part	(mineralogy) a small rounded lump of mineral substance (usually harder than the surrounding rock or sediment)
the source of lymph and lymphocytes	small rounded wartlike protuberance on a plant
(astronomy) a point where an orbit crosses a plane
(physics) the point of minimum displacement in a periodic system
(botany) the small swelling that is the part of a plant stem from which one or more leaves emerge
any thickened enlargement
a connecting point at which several lines come together