Any engine/aircraft manufacturer would define MCT as that.
Jet engine basics by Boeing on P2 page 20
This is special thrust rating, sometimes referred to as MCT or CON. It is intended to only be used only in emergency, but has no limitation.
Boeing jet transport performance methods states following:
For emergency purposes such as driftdown following an engine failure in cruise, there is a specific thrust rating called Maximum Continuous Thrust, or MCT