Aggregates

The skandhas (Sanskrit) or khandhas (Pāli) are the five functions or aspects that constitute the sentient being. In English, these five aspects are known as the five aggregates. The five aggregates are: form, sensation, perception, mental formations, and consciousness.

1. Form or matter (rūpa): external and internal matter. Externally, rūpa is the physical world. Internally, rūpa includes the material body and the physical sense organs.

2. Sensation, or feeling (vedanā): sensing an object as either pleasant, unpleasant or neutral.

3. Perception, conception, apperception, cognition, discrimination (saññā): registers whether an object is recognized or not (for instance, the sound of a bell or the shape of a tree).

4. Mental formation, impulses, volition, fabrications, compositional factors (saṅkhāra): all types of mental habits, thoughts, ideas, opinions, prejudices, compulsions, and decisions triggered by an object.

5. Consciousness, discernment (viññāṇa). 

In the Nikayas/Āgamas: the Nikayas or Āgamas: cognizance, that which discerns. In the Abhidhamma: a series of rapidly changing interconnected discrete acts of cognizance. In some Mahayana sources: the base that supports all experience.