ENGLISH
REFERENCE

fission

n. C / U
C2 Proficiency US //ˈfɪʃən// UK //fˈɪʃən// fis·sion

n. The splitting of an atomic nucleus into two or more lighter nuclei, releasing a large amount of energy. The reaction underlying nuclear power stations and atomic weapons. (In biology, also refers to single-celled organisms reproducing by splitting in two.)

n. Primarily, the splitting of a heavy atomic nucleus (typically uranium-235 or plutonium-239) into two lighter nuclei, accompanied by the release of neutrons and a large quantity of energy. The reaction underpinning both nuclear reactors and fission-based weapons. A secondary biological sense — 'binary fission' — refers to a mode of asexual reproduction in prokaryotes and some unicellular eukaryotes, where the parent cell divides into two genetically identical daughter cells.


SIMPLE

Bacteria reproduce through a process called binary fission.

CONTEXTUAL

During binary fission, the single-celled organism duplicates its genetic material and then divides into two identical parts.

COMPLEX

While nuclear fission involves splitting heavy atomic nuclei to release energy, biological fission serves as a primary mechanism for population growth in prokaryotic organisms.

Origin

Borrowed from Latin fissiōnem, accusative singular of fissiō (“the act of breaking up”), from findō (“split, divide”).

Usage

Uncountable when referring to the general process; countable when referring to specific instances of division.

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