Rapport -
Describes the feeling of trust, co-operation and acceptance that can exist between hypnotist and subject. Once rapport is established susceptibility to suggestion increases greatly. There are several plausible theories.

• The phenomenon may be due to instinctive memory, harking back to times when humans were influenced by the herd instinct as a matter of everyday survival. A group leader naturally emerged under such circumstances which the rest of the group followed. The subject temporarily allows the hypnotist to become 'herd leader'.
• It may be that in rapport the subjects unconscious mind accepts the 'likeness' of the hypnotist's conscious mind to it's own conscious mind, and temporarily allows the conscious mind of the hypnotist to take the place of its own.
• Its may be due to Authority Conditioning. From childhood we are taught the validity of authority and to respect / accept authority. So rapport may be due to the recognition of the hypnotist as an authority figure.
• It may simply be that once we have developed a certain level of trust for another person (set aside suspicion of them) we will allow them to operate within the barrier of our critical faculties.

This is not the correct place to examine the ways in which rapport is established by the hypnotist, as this is quite an abstract subject but consider the following analogy: If two tuning forks are placed side by side and one of them is caused to vibrate the other will quickly begin to vibrate too. The second fork could be said to be entrained or in rapport. This happens because the fundamental nature of the tuning forks are the same and they operate by the same laws. Likewise, rapport is quickly established between people who are fundamentally the same or who seem fundamentally the same (on the same wavelength). The skilful hypnotist must be able to quickly model the subject and temporarily adopt his world view. Of course, once rapport is established the hypnotist can then lead the subject into the process of remodelling themselves and altering their world view.
Rationalization -
From a psychological point of view rationalization is the process of explaining an action in terms of it's reasonableness. Usually this is an action that the patient is not particularly proud of but hopes to diminish feelings of guilt by showing the act to follow natural logic. Specious excuse.
From a hypnosis point of view rationalization is where a subject seeks to explain his actions in hypnosis or post hypnotic suggestion in a 'reasonable fashion'. 
For example, a subject is hypnotized and told that every time the hypnotist claps his hands the subject will remove his jacket. This suggestion can be tested several times and each time the subject will remove his jacket but when asked why he keeps doing this he will rationalize and say something like, "It keeps getting warm in here", or "I don't feel comfortable wearing it."
Reactive Depression -
This is depression caused by a specific identifiable occurrence, such as the loss of a loved one. Can be treated with hypnosis but all cases of depression must be approached with caution. It is wise to seek referral from the patient's doctor.
Reciprocal Inhibition -
A term from behaviour therapy which is defined because of its use within hypno-desensitization. Reciprocal inhibition occurs when an anxiety inducing stimulus in made to happen at the same time as an anxiety inhibiting response (such as deep relaxation) then the anxiety inducing stimulus will begin to lose it's ability to evoke anxiety. For example, if a patient is made to relax completely while experiencing something that would normally make them anxious or provoke a phobic reaction, the ability of that thing to cause a reaction will be diminished.
Regression -
From the point of view of hypnosis, regression is the process of taking subjects back into their own past to reexperience memories. Dissociation in time. Some subjects can be regressed beyond birth and appear to provide information about experiences in previous lives.
Rehearsal -
The method of obtaining psychological experience by practising events in imagination as if they were actually occurring. Useful for goal orientation.
Relaxation -
Removing the will to move (or state of readiness) from the bodies muscles. Lack of tension, leading to a comfortable stillness.
REM Sleep-
Rapid Eye Movement sleep, characteristic of the dream state.
Repression -
One of the earliest concepts of psychoanalysis. The theory is that a psychic function exists which seeks to prevent certain emotionally charged memories from coming to consciousness by keeping them deep in the unconscious mind. It is claimed that these 'repressed memories' are the dynamic source of neurosis and maladapted behaviour. Whether there is such a repressing function is open to debate, never the less the mind does seem to work as if there is. Experience has proven that unearthing and expressing the energy of these 'imprisoned' memories can lead to the relief of symptoms. 
Resistance -
In hypnosis this refers to the opposition sometimes faced by hypnotists when trying to induce hypnosis in a subject. This is usually unconscious resistance due 
deep rooted fear or distrust and so can occur even when the subject consciously desires to be hypnotized. The hypnotists will need to establish strong rapport and work on the fear first. Every normally functioning human can be hypnotized.
RAS, Reticular Activating System -
Refers to a part of the brain which functions to govern wakefulness and sleep.
Retrograde Amnesia -
Inability to recall memories before a certain event. For example a person might not be able to remember anything that happened before an accident but can remember everything that has happened since. 
Reverie -
When the mind drifts into daydreams or fantasy.
Revivification -
Literally, to bring back to life or reanimate. Refers to regression experience where the subject fully reexperiences that time and adopts all the characteristics of the period. For example a subject regressed to the age of 5 who is revivifying has no memory of anything after that age and will speak, act and think as a five year old.