nuclei

1. a part of the cell containing DNA and RNA and responsible for growth and reproductionSynonyms: cell nucleus, karyon, nucleus

2. the positively charged dense center of an atomSynonyms: nucleus

3. a small group of indispensable persons or thingsExamples: "five periodicals make up the core of their publishing program"Synonyms: core, core group, nucleus

4. (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 tailSynonyms: nucleus

5. any histologically identifiable mass of neural cell bodies in the brain or spinal cordSynonyms: nucleus

6. the central structure of the lens that is surrounded by the cortexSynonyms: lens nucleus, nucleus