Nucleus

How to spell nucleus

7 letters · 3 syllables

How to pronounce nucleus

Say the part in capitals loudest.

What does nucleus mean?

1. nounThe central, most important part of something, such as the core of an atom or the control centre of a living cell.

Nucleus in a sentence

• The nucleus of an atom contains protons and neutrons.

• Under the microscope the dark nucleus of the cell was clearly visible.

Where does nucleus come from?

Language of origin: Latin

This word comes directly from the Latin nucleus, meaning a kernel or the inner part of something, especially the edible core of a nut. It was a diminutive of nux (genitive nucis), the ordinary Latin word for 'nut', so the literal sense was something like 'little nut'. English adopted nucleus in the early 1700s as a scientific term, first describing the central kernel of various natural objects, and astronomers used it for the bright core of a comet. As cell biology and then atomic physics developed in the 1800s and 1900s, the word was attached to the central body of a living cell and to the dense core of an atom. The spelling preserves the Latin -eus ending and the cle cluster, which is the part writers most often stumble over, and the same nux root survives in the everyday word 'nut'.

How the word is built

• nucle- (from Latin nucleus: kernel, little nut)
• -us (Latin noun ending)