What's the difference between a Christening and a Baptism?

Some churches use the words interchangably but technically, christening is the sprinkling of water on a childs head to signify the washing away of sin....and baptism is the complete submersion of the entire body into water...to signify the same thing by the way. Submersion baptism is used primarily by churches who feel that the individual person must make a decision on their own to follow God/Jesus...and that the wishes of the parents do not matter...as in a christening/baptism of infants. Thus, baptism does not take place until the youngster is wise enough in the spirit to be able to make that committment.