A small round body of protein in a cell nucleus

• Nucleoli contain RNA and are involved in protein synthesis

Wikipedia Word definitions in Wikipedia
The nucleolus ( or , plural nucleoli or ) is the largest structure in the nucleus of eukaryotic cells , where it primarily serves as the site of ribosome synthesis and assembly. Nucleoli also have other important functions like assembly of signal recognition ...

WordNet Word definitions in WordNet
n. a small round body of protein in a cell nucleus; nucleoli contain RNA and are involved in protein synthesis [syn: nucleole ] [also: nucleoli (pl)]

Wiktionary Word definitions in Wiktionary
n. (context cytology English) A conspicuous, rounded body within the nucleus of a cell.

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
1845, from Latin nucleolus , literally "a little nut," diminutive of nucleus (see nucleus ).

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Nucleolus \Nu*cle"o*lus\, n.; pl. Nucleoli . [L., a little nut, dim. of nucleus.] A little nucleus. (Biol.) A small rounded body contained in the nucleus of a cell or a protozoan. Note: It was termed by Agassiz the entoblast. In the protozoa, where it may ...