Happiness is a state of mind or feeling such as contentment, satisfaction, pleasure, or joy.[1] A variety of philosophical, religious, psychological and biological approaches have been taken to defining happiness and identifying its sources.

Philosophers and religious thinkers have often defined happiness in terms of living a good life, or flourishing, rather than simply as an emotion. Happiness in this older sense was used to translate the Greek Eudaimonia, and is still used in virtue ethics. In everyday speech today, however, terms such as well-being or quality of life are usually used to signify the classical meaning, and happiness usually refers[citation needed] to the felt experience or experiences that philosophers historically called pleasure.

While direct measurement of happiness presents challenges, tools such as The Oxford Happiness Questionnaire have been developed by researchers. Positive psychology researchers use theoretical models that include describing happiness as consisting of positive emotions and positive activities, or that describe three kinds of happiness: pleasure, engagement, and meaning.

Research has identified a number of attributes that correlate with happiness:[citation needed] relationships and social interaction, parenthood, marital status, religious involvement, age, income (but mainly up to the point where survival needs are met), and proximity to other happy people.