What is Faith?
Faith, pure faith, accepts or rejects without basis of reason, beyond the scope of that which is perceived through the five senses. Faith is the substance of things hoped for, the evidence of things not seen. This is why some scientists and sudo scientists (Atheists) have a problem with those who have faith.
What constitutes a higher power?
This depends on the ideal of the individual, and at what height the ideal is set. It can include a material goal like money or a spiritual goal like oneness with God, as well as anything in between. The higher the ideal the greater the achievement that's possible, so why limit yourself and be an underachiever.