There is no consensus on a single definition of well-being. However, within MDH and SHIP there is a consensus that well-being includes positive emotions and moods, absence of negative emotions, satisfaction, fulfillment and positive functioning.
Other considerations when thinking about well-being are mental health, resiliency, and risk & protective factors.
Mental health: "A state of well-being in which the individual realizes their own abilities, can cope with the normal stresses of life, can work productively and fruitfully, and is able to make a contribution to their community." - World Health Organization
Another way to think about mental health and well-being is to look at the dual continuum.
Pay special attention to flourishing!