nucleolus vs nucleus

nucleolus and nucleus both are nouns.

Word	Noun	Adjective	Verb	Adverb
nucleolus	Yes	No	No	No
nucleus	Yes	No	No	No

nucleolus (noun)	nucleus (noun)
a small round body of protein in a cell nucleus; such organelles contain RNA and are involved in protein synthesis	a part of the cell containing DNA and RNA and responsible for growth and reproduction
	any histologically identifiable mass of neural cell bodies in the brain or spinal cord
	the central structure of the lens that is surrounded by the cortex
	a small group of indispensable persons or things
	the positively charged dense center of an atom
	(astronomy) the center of the head of a comet; consists of small solid particles of ice and frozen gas that vaporizes on approaching the sun to form the coma and tail