The dictionary definition of resilience is: the capacity to recover quickly from difficulties; the ability of a substance or object to spring back into shape; elasticity. It's a subject of great interest at the moment because many of us are having our ability to "bounce back" tested by the coronavirus.
A model that comes up a lot is Elisabeth Kubler-Ross' five stages of grief theory, which was published in the late 1960's. Her experience with terminally ill patients led her to observe a pattern of thinking that people go through when facing death either themselves or in a loved one. This theory was later found to apply to all kinds of personal loss including disability, redundancy, divorce and financial problems. It's not a linear process: people can go through it at any pace, in any order and often experience cycles of it.
These are the phases:
25 years experience in helping teams build user centred products and services, now helping digital colleagues find their happy path at work