4

4 classical elements

4 aims of human life: Dharma, Artha, Kāma, Moksha

4 freedoms

4 fundamental forces (physics)

4 causes (aristotle)

4 categories (stoic)

4 categories (Kant)

4 steps in the OODA loop

4 colors in CMYK

4 cardinal directions

4 temperaments (hippocrates)

4 suits

4 mindfulness steps in Satipatthana

4 components in Iddhipada

4 right extersions in Sammappadhāna