The five skandhas are five elements or "aggregates" said to constitute human experience in Buddhism. Since individual experience is a product of the five skandhas, there is no true self. Suffering is said to arise from identifying with the five skandhas, while freedom can come from recognizing the emptiness of the five skandhas and the nonexistence of self.
The five skandhas are form, consciousness, feeling, perception, and formation. The world, or samsara, also understood as the cycle of reincarnation, is experienced exclusively through the skandha. Form, or rūpa, is anything physical, both the outside world and the body itself, including sense organs. Form is divided into the mahābhūta or four great elements: earth, fire, air, and water. Every part of physical matter, including the human body, is reduced to these four elements.
Consciousness, or vijñāna, is also known as life-force or mind. It arises from the interaction of the other skandhas. The other three skandhas together constitute the mental factors, or cetasika.
The first of the cetasika is feeling, or vedanā, which includes anything experienced through the five senses. Perception, or saññā, is the recognition of something experienced through the senses, for example, the perception of the color green or the sound of a bell ringing. Formation, or sankhāra, is all mental activity that results from their perception of an object.
The five skandhas are considered to be the source of human suffering, since people cling to them or experience craving rather than simply experiencing them. For example, most people have a sense of self arising from the interaction of the five skandhas, so when the body inevitably experiences age and illness, they feel a loss of self and consequently mental anguish in addition to physical pain. The path to enlightenment, or nirvana, requires recognizing the five skandhas as impermanent and empty and losing one's attachments to them, ultimately attaining "non-self" or anatta. This is generally accomplished through meditation.