On the one hand, hypnosis refers to the method, the technique, which is important for achieving the hypnotic trance. On the other hand, hypnosis refers to the actual state of hypnotic trance achieved, which involves a physical and psychological change. The term hypnosis comes from the Greek word "hypnos". Hypnos means as much as sleep. However, hypnosis as it is used today is by no means sleep. Most likely, this state could be called sleep-like or semi-sleep-like. Many describe hypnosis as a kind of intermediate state - between being awake and asleep with various trance depths.
Here is an in-depth post about hypnosis: What Is Hypnosis?