The maintenance and improvement of physical and mental health, especially through the provision of medical services. (Oxford Dictionaries)
Oxford Dictionaries. s.v. "healthcare." Accessed February 18, 2016. http://www.oxforddictionaries.com/us/definition/american_english/healthcare
The term healthcare generally sometimes is used to refer only to the improvement of physical or mental health; i.e. to the delivery of medical care after there is an issue. This broader definition was chosen to encompass preventive approaches to healthcare as well.