nucleus
/ˈnjuːklɪəs/noun
(pl. nuclei /-klɪaɪ/)
1- the central and most important part of an object, movement, or group, forming the basis for its activity and growth核心：
the nucleus of a British film-producing industry.
英国电影制作业的核心。
1.1
- Astronomy the solid part of a comet's head【天文】（彗星的）核。
1.2
- Physics the positively charged central core of an atom that contains most of its mass【物理】原子核。
1.3
- Biology a dense organelle present in most eukaryotic cells, typically a single rounded structure bounded by a double membrane, containing the genetic material【生】细胞核。
1.4
- a discrete mass of grey matter in the central nervous system神经核。
词源
early 18th cent.: from Latin， literally 'kernel， inner part'， diminutive of nux, nuc- 'nut'.