Yama – external restraints
Moral disciplines or moral vows
Consists of five parts

Ahimsa

Non-violence. Not harming. 

Satya

Honesty. Being truthful.

Asteya

Not stealing. Not being envious.

Brahmacharya

Wise use of energy – including sexual energy. The preservation of body fluids. 

Aparigraha

Not accumulating more than needed – including eating too much.