World Health Organisation (WHO): "Health is the state of complete physical, mental and social well-being and not merely an absence of disease or infirmity" (old definition).
WHO : "Attainment of life to lead a socially and economically productive life." (new definition)
J.F. William : "It is the quality of life to live most and serve the best."
Webster's Encyclopaedia : "It is the state of individual to mobilise his resources intellectually, emotionally and physically for optimum living."
Voltmer & Esslinger: "Health is considered as that mental and physical condition in which individual is functionally well-adjusted internally as concern of body parts and externally as concern of environment."