Scope of claims

U.S. Patent Law
Under 35 U.S.C. §112 the the scope of a claim is defined based on the particular and distinct claim given in the specification of the patent.

Courts
The words of the claim themselves define the scope of the patented invention. Further, the words of a claim are "generally given their ordinary and customary meaning." Said ordinary and customary meaning is "the meaning that the term would have to a person of ordinary skill in the art in question at the time of the invention."