Fission

How to spell fission

7 letters · 2 syllables

How to pronounce fission

Say the part in capitals loudest.

What does fission mean?

1. nounThe splitting of a heavy atomic nucleus into lighter parts, releasing a large amount of energy.
2. nounA form of asexual reproduction in which a single organism divides into two or more parts.

Fission in a sentence

• The reactor generates electricity through controlled nuclear fission.

• Many bacteria multiply rapidly through binary fission.

• The physics lecture explained how fission releases enormous amounts of heat.

• The biology textbook described how amoebas reproduce by fission.

Where does fission come from?

Language of origin: Latin

This word traces back to the Latin verb findere, meaning 'to split' or 'to cleave', whose past participle fissus gave the late Latin noun fissio, literally 'a splitting'. English adopted it in the early nineteenth century, first as a scientific term in biology to describe the way certain single-celled organisms reproduce by dividing in two. The far more famous sense arrived in 1939, when physicists needed a word for the splitting of a heavy atomic nucleus and borrowed the existing biological term, which then leapt into headlines during the atomic era. The same Latin findere root lies behind 'fissure', a narrow crack, and that family connection is a useful reminder that the heart of the word is the idea of splitting apart. The spelling trap is the double s followed by -ion: it sounds like the casual 'fishin'', but the letters are fiss-ion, mirroring fissure.

How the word is built

• fiss- (from Latin fissus 'split, cleft')
• -ion (noun of action)