Five Aggregates (pañca-khandhā) 
오온

The theory of the five aggregates, or “pañca-khandhā,” is an excellent Buddhist classification system which analyzes human existence. In this system, human existence is divided into five components: form, feeling, perception, mental formations and consciousness. Because the five aggregates constantly change, they are impermanent and therefore, bring suffering. There is no "self" in these five impermanent aggregates (non-self or anatman). A human being is only a temporary collection of these five aggregates. As such, there is no single component of the five aggregates which can be claimed as “self,” but sentient beings continually hold on to their belief in self. This belief comes from the five aggregates of attachment. 

Form (rūpa): Materiality or the physical body
Feeling (vedana): Receptive or sensory functions of consciousness
Perception (saññā): Function of consciousness which forms concepts, perceptions and symbols

Mental formations (saṅkhāra): Intentions or behavioral needs which are active mental functions not included in the aggregates of feeling or perception

Consciousness (viññāṇa): Mental functions which perceive an object through discrimination, judgment and integration 

- excerpt from Buddhist English (Elementary 2) published in 2014 by the Jogye Order of Korean Buddhism​​​