jõuvaruna
Jõuvaruna is an Estonian term that translates to "power reserve" or "energy reserve." It commonly refers to the surplus of energy a system, such as a person, machine, or even an ecosystem, possesses beyond its immediate operational needs. This reserve allows the system to cope with unexpected demands, fluctuations, or periods of scarcity.
In a biological context, jõuvaruna might describe the energy stores in an organism that can be mobilized
For mechanical systems, jõuvaruna can indicate the extra capacity of a motor or engine that allows it