Yama: Precepts of Social Discipline Ahimsa -- Non-violence. Not harming other people or other sentient beings. Not harming onesself. Not harming the environment. Tolerance even for that which we dislike. Not speaking that which, even though truthful, would injure others.
Satya -- Truthfulness. Note that sometimes we may know our words are literally true, but do not convey what we know to be truthful. This is a child's game. Satya means not intending to deceive others in our thoughts, as well as our words and actions.
Asteya -- Non-stealing. Not taking that which is not given.
Brahmacharya -- Sexual responsibility. Regarding others as human beings rather than as male and female bodies. The spirit of this precept is conservation of energy for the purpose of spiritual practice. This includes not only sexual restraint, but protecting our energy for instance by avoiding endless chattering with no clear purpose.
Aparigraha -- Abstention from greed. Not coveting that which is not ours. Avoidance of unnecessary acquisition of objects not essential to maintaining life or spiritual study.
Niyama: Precepts of Invididual Discipline
Sauca -- Cleanliness. Not only external cleanliness of the body, but attending to internal cleanliness such as avoiding the impurities of anger and egoism. Moderation in diet.
Santosa -- Contentment. Not spiritual complacency, but acceptance of the external situation we are allotted in this life.
Tapas -- Austerity. Deep commitment to our yoga practice. "Blazing practice with religious fervor."
Svadhyaya -- Self-study. Spiritual self-education. Contemplation and application of the scriptures or sacred texts of our chosen path.
Isvara pranidhana -- Surrender of the self to God. Acknowledgement that there is a higher principle in the universe than one's own small self. Modesty. Humility.