An emotion is a mental and physiological state associated with a wide variety of feelings, thoughts, and behavior. Emotions are subjective experiences, or experienced from an individual point of view. Emotion is often associated with mood, temperament, personality, and disposition. The English word 'emotion' is derived from the French word émouvoir. This is based on the Latin emovere, where e- (variant of ex-) means 'out' and movere means 'move'. The related term "motivation" is also derived from movere.

No definitive taxonomy of emotions exists, though numerous taxonomies have been proposed. Some categorizations include:

• 'Cognitive' versus 'non-cognitive' emotions
• Instinctual emotions (from the amygdala), versus cognitive emotions (from the prefrontal cortex).
• Basic versus complex: where base emotions lead to more complex ones.
• Categorization based on duration: Some emotions occur over a period of seconds (e.g. surprise) where others can last years (e.g. love).

A related distinction is between the emotion and the results of the emotion, principally behaviours and emotional expressions. People often behave in certain ways as a direct result of their emotional state, such as crying, fighting or fleeing. Yet again, if one can have the emotion without the corresponding behaviour then we may consider the behaviour not to be essential to the emotion. The James-Lange theory posits that emotional experience is largely due to the experience of bodily changes. The functionalist approach to emotions (e.g. Nico Frijda) holds that emotions have evolved for a particular function, such as to keep the subject safe.

Classification

Basic and complex categories, where some are modified in some way to form complex emotions (e.g. Paul Ekman). In one model, the complex emotions could arise from cultural conditioning or association combined with the basic emotions. Alternatively, analogous to the way primary colors combine, primary emotions could blend to form the full spectrum of human emotional experience. For example interpersonal anger and disgust could blend to form contempt.Fact: date=March 2009

Robert Plutchik proposed a three-dimensional "circumplex model" which describes the relations among emotions. This model is similar to a color wheel. The vertical dimension represents intensity, and the circle represents degrees of similarity among the emotions. He posited eight primary emotion dimensions arranged as four pairs of opposites. Some have also argued for the existence of meta-emotions which are emotions about emotions., "Meta-emotions".Fact: date=March 2009

Another important means of distinguishing emotions concerns their occurrence in time. Some emotions occur over a period of seconds (e.g. surprise) where others can last years (e.g. love). The latter could be regarded as a long term tendency to have an emotion regarding a certain object rather than an emotion proper (though this is disputed). A distinction is then made between emotion episodes and emotional dispositions. Dispositions are also comparable to character traits, where someone may be said to be generally disposed to experience certain emotions, though about different objects. For example an irritable person is generally disposed to feel irritation more easily or quickly than others do. Finally, some theorists (e.g. Klaus Scherer, 2005) place emotions within a more general category of 'affective states' where affective states can also include emotion-related phenomena such as pleasure and pain, motivational states (e.g. hunger or curiosity), moods, dispositions and traits.Fact: date=March 2009