For most working class people today, this is a word that has become normal.
I could define burnout as a build up of fatigue that causes one to become emotionally, mentally and physically drained. A common cause of this is stress.
There is a difference between stress and burnout by the way.
Stress is defined by dictionary.com as physical, mental, emotion strain or tension. It also defines burnout as frustration or apathy resulting from prolonged stress, overwork or intense activity.
These days, stress seems to be part of our everyday lives. How we manage stress and eventually burnout matters to our well being.