1. past tense of fission; split or divided into parts, especially through nuclear fission
Usage: scientific

Examples

• The uranium atom fissioned when struck by a neutron.
• Scientists observed how the nucleus fissioned into smaller fragments.
• The radioactive material fissioned spontaneously.
• In the reactor, atoms fissioned to release enormous energy.
• The heavy element fissioned into two lighter nuclei.
• Researchers studied how plutonium fissioned under controlled conditions.