nucleus

Everyday

1. (science) The nucleus is the centre of a cell that holds its DNA and controls it. tree →
2. (science) The nucleus of an atom is its tiny centre, made of protons and neutrons. tree →
3. A nucleus is the central or most important part of a group or thing, as in the nucleus of a team. tree →

In the lessons

In biology lessons, plant and animal cells have a nucleus; bacteria do not. In chemistry and physics, the atom's nucleus holds almost all its mass, with electrons around it; nuclear energy comes from it. In everyday talk, a few key players form the nucleus of a team.

Examples

• The nucleus controls what the cell does. tree →
• Plant and animal cells both have a nucleus. tree →
• The nucleus of an atom contains protons and neutrons. tree →
• We drew the nucleus in the middle of our cell diagram. tree →
• Nuclear power comes from splitting the nucleus of atoms. tree →
• These five players are the nucleus of the team. tree →
• The latter scholar has proved that there is a nucleus of stories in every European land which is common to all. tree →

Note

Plural: nuclei (said NEW-klee-eye). Adjective: nuclear. Said NEW-klee-us (UK) or NOO-klee-us (US). Trap: nuclear is often mispronounced nucular.