strong interaction
In particle physics, the fundamental force that binds quarks together inside protons and neutrons, and holds the atomic nucleus together.
The strong interaction binds protons and neutrons together inside the atomic nucleus.
The weak interaction is another fundamental force, responsible for certain types of radioactive decay; it is much weaker than the strong interaction and acts over a shorter range.
Electromagnetic interaction governs electric and magnetic forces; unlike the strong interaction, it acts on charged particles and has an infinite range.
Gravitational interaction is the weakest fundamental force, acting between masses; it is negligible at the subatomic scale compared to the strong interaction.
Compound of 強い (strong) + 相互作用 (interaction), a calque of the English physics term 'strong interaction'.