nucleolus vs organelle

nucleolus and organelle both are nouns.

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

As nouns, organelle is a hypernym of nucleolus; that is, organelle is a word with a broader meaning than nucleolus:

nucleolus: a small round body of protein in a cell nucleus; such organelles contain RNA and are involved in protein synthesis
organelle: a specialized part of a cell; analogous to an organ

Other hypernyms of nucleolus include cell organ, cell organelle.

nucleolus (noun)	organelle (noun)
a small round body of protein in a cell nucleus; such organelles contain RNA and are involved in protein synthesis	a specialized part of a cell; analogous to an organ