Asana: An asana is the physical yoga posture.
Pranayama: the literal meaning of Pranayama is an extension the Prana. This is the vital life force energy. Thus the objective of Pranayama is to awaken, commune, regulate and direct the vital life force that exist in the body.
"Pranayama is what heart is to the human body." B.K. Iyengar: Light on the Yoga Sutras of Patanjali
Yamas:
Ahimsa: Non-Harming. To focus on the cessation of harming at the levels of action, speech, and thoughts. As a Yogi becomes firmly grounded in non-injury (ahimsa) other people who come near will naturally lose any feelings of hostility.
Satya: Truthfulness. For one who practices honesty or truthfulness in actions, speech, and thoughts, his or her will is naturally fulfilled.
Asteya: Non-stealing. When non-stealing (asteya) is established, all jewels, or treasures present themselves, or are available to the Yogi.
Brahmacharya: Mindfulness of higher truth . When walking in the awareness of the highest reality (bramacharya) is firmly established, then a great strength, capacity, or vitality is acquired.
Aparigraha: Non-Acquisitiveness. When one is steadfast in non-possessiveness or non-grasping with the senses (aparigraha), there arises knowledge of the why and wherefore of past and future incarnations.
Niyamas (Observances or codes for living soulfully):
Saucha: Purity of body and mind. Also through cleanliness and purity of body and mind (shaucha) comes a purification of the subtle mental essence (sattva), a pleasantness, goodness and gladness of feeling, a one-pointed ness with intentness, the conquest or mastery over the senses, and a fitness, qualification, or capability for self-realization.
Santosha: Contentment. From an attitude of contentment (santosha), unexcelled happiness, mental comfort, joy, and satisfaction is obtained.
Tapas: Training the senses. Through ascesis or training of the senses (tapas), there comes a destruction of mental impurities, and an ensuing mastery or perfection over the body and the mental organs of the sense and actions.
Svadhyaya: Self-study. From self-study and reflection on sacred words (svadhyaya), one attains contact, communion, or concert with that underlying natural reality or force.
Ishvarapranidhana: Practicing the presence, or surrender. From an attitude of letting go, practicing the presence, dedication, or surrender into the creative source, causal field, God, supreme Guru or teacher (ishvarapranidhana), the state of perfected concentration (samadi) is attained.
*Quoted from the Yoga-Sutra of Patanjali