atomic nucleus, the collection of protons and neutrons in the center of an atom that carries the bulk of the atom's mass & caring charge cell nucleus, the membrane-bound subcellular organelle found in eukaryotes, visible via microscopy, which contains, primarily, the cell's chromosomes nucleus, a term inside neuroanatomy used to describe a central nervous system structure composed mainly of gray matter that mediates electrical signaling in the particular subsystem comet nucleus, the firm core of the comet galaxy nucleus, the central vicinity of the galaxy ice nucleus, the center of an snow mist. cloud condensation nuclei, the basis for the development of the cloud droplet syllable nucleus, the central the share of a syllable sentence nucleus, the syllable which receives the greatest stress within a word Nucleus CMS, an open-source weblog system a kernel of an operating system Nucleus RTOS, a brand of operating system Nucleus, a British jazz-rock band led by Ian Carr

Etymology
Nucleus is New Latin, diminutive of the Latin nux (nut).

ca:Nucli de:Kern es:Núcleo gl:Núcleo ko:핵 ia:Nucleo is:Kjarni it:Nucleo nl:Nucleus