Definition from Nolo’s Plain-English Law Dictionary
Statements included in a patent that describe (or recite) the structure of an invention in precise and exact terms, using a long-established formal style and precise terminology. Claims form the boundaries of an invention much like a deed describes the boundaries of real property. They may be broad or narrow in terms of the scope of the invention they address. The greater the scope of the invention defined in the claims (that is, the broader the claims), the wider the reach of the patent.