Health is a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity.
The correct bibliographic citation for the definition is:
Preamble to the Constitution of the World Health Organization as adopted by the International Health Conference, New York, 19-22 June, 1946; signed on 22 July 1946 by the representatives of 61 States (Official Records of the World Health Organization, no. 2, p. 100) and entered into force on 7 April 1948.