fission

1 of 2

noun

fis·​sion ˈfi-shᵊn  -zhᵊn 

1

: a splitting or breaking up into parts

2

: reproduction by spontaneous division of the body into two or more parts each of which grows into a complete organism

3

: the splitting of an atomic nucleus resulting in the release of large amounts of energy

fissional

ˈfi-shə-nəl  -zhə- 

adjective

fission

2 of 2

verb

fissioned; fissioning; fissions

intransitive verb

: to undergo fission

transitive verb

: to cause to undergo fission

Examples of fission in a Sentence

Recent Examples on the Web

Noun

The reason for the frantic efforts to stabilize the reactors and spent fuel pools is that if the situation were to deteriorate further, molten and vaporized fuel could release dangerous radioactive fission products such as Cesium-137. —Victor Gilinsky, Foreign Affairs, 21 Mar. 2011

These fission reactors use water to slow down the neutrons and to absorb and transfer heat. —Dan Kotlyar, Discover Magazine, 5 Oct. 2024

Verb

Most atoms do not fission, but the isotopes of certain elements, such as uranium-235, are fissile. —Washington Post, 28 Apr. 2022

The point is that by analyzing the array of radioactive fission products – those that can be captured and analyzed – nuclear forensic specialists can start to figure out if the atoms that fissioned were U-235, Pu-239, or (in some cases) U-238. —Andrew Karam, Popular Mechanics, 7 Jan. 2016

Word History

Etymology

Noun

borrowed from Latin fissiōn-, fissiō, from fid-, variant stem of findere "to split, cleave" + -tiōn-, -tiō, suffix of verbal action — more at bite entry 1

Verb

derivative of fission entry 1

First Known Use

Noun

circa 1617, in the meaning defined at sense 1

Verb

1929, in the meaning defined at intransitive sense

Phrases Containing fission

• binary fission
• nuclear fission

Kids Definition

fission

1 of 2 noun

fis·​sion ˈfish-ən 

 also  ˈfizh-

1

: a splitting or breaking up into parts

2

: a method of reproduction in which a living cell or body divides into two or more parts each of which grows into a whole new individual

3

: the splitting of an atomic nucleus resulting in the release of large amounts of energy

fission

2 of 2 verb

fissioned; fissioning

ˈfish-(ə-)niŋ,

ˈfizh-

: to go through or cause to go through fission

Medical Definition

fission

noun

fis·​sion ˈfish-ən also ˈfizh- 

1

: a method of reproduction in which a living cell or body divides into two or more parts each of which grows into a whole new individual

2

a

: cleavage sense 2

b

: the splitting of an atomic nucleus resulting in the release of large amounts of energy

called also nuclear fission

fission verb

fissioned; fissioning ˈfish-(ə-)niŋ also ˈfizh- 

fissional

ˈfish-ən-ᵊl also ˈfizh- 

adjective