n. | 1. | |
1. | A kernel; hence, a central mass or point about which matter is gathered, or to which accretion is made; the central or material portion; - used both literally and figuratively. | |
2. | (Astron.) The body or the head of a comet. | |
3. | (Bot.) An incipient ovule of soft cellular tissue. | |
4. | (Biol.) A body, usually spheroidal, in a eukaryotic cell, distinguished from the surrounding protoplasm by a difference in refrangibility and in behavior towards chemical reagents, which contains the chromosomal genetic material, including the chromosomal DNA. It is more or less protoplasmic, and consists of a clear fluid (achromatin) through which extends a network of fibers (chromatin) in which may be suspended a second rounded body, the nucleolus (see Nucleoplasm). See | |
5. | (Zool.) The tip, or earliest part, of a univalve or bivalve shell. |
Noun | 1. | ![]() Synonyms: cell nucleus, karyon |
2. | nucleus - the positively charged dense center of an atom | |
3. | nucleus - a small group of indispensable persons or things; "five periodicals make up the core of their publishing program" Synonyms: core group, core | |
4. | nucleus - (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 | |
5. | nucleus - any histologically identifiable mass of neural cell bodies in the brain or spinal cord |