under control
prep_phrase1
Idiomatic Being taken care of or being addressed.
- Don't worry; the police have been called and the situation is under control.
2
Being actively controlled, or able to be actively controlled in its current state.
- Throughout the turbulence encounter, the pilots kept the aircraft under control.
- The control rods absorb neutrons in the reactor core, keeping the fission reaction under control and preventing it from going prompt critical.