Hypnosis is an altered state of awareness. It is when you are in a state of awareness that is other than your normal waking or sleeping states. Also you can consider it a state of focused concentration when the conscious mind has moved to one side and the unconscious mind is more active. The state that is out of conscious awareness is called the trance state.
Hypnosis allows the unconscious mind to be accessed more easily. You are more accepting of suggestions, changing mental patterns, physiology and emotions. Hypnosis takes you into the trance state so you can access the vast resources of your unconscious mind, which has a lifetime of resources.