Commission has a lot of meanings. Some of these are similar because of the root word 'commit'. For example: Commission: A very formal word, not used much. A duty that a person or group is given. Often an authority gives this duty without the choice of the person receiving it. Examples: - a soldier's orders. - In christian theology "The great commission" is the final job that Jesus gave his followers" - a special committee appointed by a government to investigate something. - Being given such a duty is called being commissioned. A commitment is normally a more voluntary duty. E.g. "I have commitments to work, commitments to my wife and children." "When we got married, I made a commitment to my wife to care for her" "Our company has made a commitment to our customers to providing good service." Other definitions are totally different, for example commission of a crime. Some senses of commitment imply exclusivity: Commitment to my wife Which TV will I buy? I must commit to one (make a commitment).

They're completely different. Have you checked a dictionary? Try posting some sample sentences!