nucleus

plural nuclei · plural nucleuses

1. The core, central part of something, around which other elements are assembled.

   1 more example

   Situated in the centre of the largest agricultural basin in northern Formosa, T’ai-pei (population in 1964 was estimated to be 1,117,000) forms the nucleus of a major industrial area. The T’ai-pei industrial complex includes light and heavy industies within the urbanized area and also in several industrial suburbs, including Pan-ch’iao and Nan-chiang.

   1968, Norton S. Ginsburg, “T’AI-PEI”, in Encyclopedia Britannica, volume 21, →LCCN, →OCLC, page 627, column 2

2. An initial part or version that will receive additions.

   This collection will form the nucleus of a new library.

   2 more examples

   The nucleus of this huge compilation [the Mahabharata] may date from the fifth century before Christ; through successive expansions it attained its present enormous bulk in the early centuries of our era.

   1918, James George Frazer, Folk-Lore In The Old Testament, volume 1, page 185

   This publishing project and the experience Power gained from wartime activities formed the nucleus for the development of the giant enterprise that today is University Microfilms, subsidiary of the Xerox Education Group, Xerox Corporation.

   1972, Carol A. Nemeyer, Scholarly Reprint Publishing in the United States, New York, N.Y.: R. R. Bowker Co., →ISBN, page 49

3. chemistryThe massive, positively charged central part of an atom, made up of protons and neutrons.
4. biologyA large membrane-enclosed organelle found in eukaryotic cells which contains genetic material.
5. anatomyA ganglion, cluster of many neuronal bodies where synapsing occurs.
6. human sciencesThe central part of a syllable, most commonly a vowel.
7. agricultureA small bee-hive used to create a colony from a larger existing one.