The ability to prepare for and adapt to changing conditions and recover rapidly from operational disruptions. Resilience includes the ability to withstand and recover from deliberate attacks, accidents, or naturally occurring threats or incidents.

 Source: FCD-1

Merriam-Webster Online Dictionary
resilience (noun)
the capability of a strained body to recover its size and shape after caused especially by compressive stress - deformation
an ability to recover from or adjust easily to or change - misfortune
Resilience is the ability to recover quickly from difficulties and bounce back from adversity. It is the capacity to adapt to changing circumstances and to cope with difficult situations.