Reasonable suspicion and so forth

Define Reasonable Suspicion, Probable Cause, and Proof Beyond a Reasonable Doubt. Also explain what authority each level of information gives government.
Reasonable Suspicion:
To conduct a Terry search, or a stop and frisk, police need reasonable suspicion that the person is suspected of imminent illegal behavior or past criminal activity. Reasonable suspicion is based on the totality of the circumstances as understood by those versed in the field of law enforcement; it is commonly described as something more than a hunch, but less than probable cause.
Probable Cause:
In the United States criminal court system, probable cause refers to facts or evidence that would make a reasonable person believe that a crime or wrong doing has been, is being, or will be committed.
Proof beyond a reasonable doubt:
Beyond a reasonable doubt is the highest standard of proof that must be met in any trial. In civil litigation, the standard of proof is either proof by a PREPONDERANCE OF THE EVIDENCE or proof by clear and convincing evidence. These are lower burdens of proof. This is the standard that must be met by the prosecution.