Definition(s):

“Wellness is a multidimensional state of being describing the existence of positive health in an individual as exemplified by quality of life and a sense of well-being.” (Corbin & Pangrazi)
I would propose a …definition of wellness, health promotion, and disease prevention, as follows:
“A set of organized activities and systematic interventions, offered through corporations/worksites, managed care organizations, and governmental/community agencies, whose primary purposes are to provide health education, identify modifiable health risks, and influence health behavior changes.” (Mulyihill)

Corbin, C.B. & Pangrazi, R.P. (2001). Toward a uniform definition of wellness: A commentary. President’s Council on Physical Fitness and Sports Research Digest, 3(15), 1-8. Mulvihill, M. (2003). The definition and core practices of wellness. Journal of Employee Assistance, 33(3), 13-15.