An invention is a new composition, device, or process. Invention can also be defined to include creative endeavors that extend beyond original, substantial improvements. An invention is also a new, useful, and nonobvious improvement of a process, machine, or product. Any invention which is new, useful, and nonobvious improvement of process can be patented. Inventions that involve processes, machines, manufactures, and compositions of matter, and any improvement thereof, are patentable.
In the United States, Congress has not made any attempts to define the term 'invention' either under older laws or under the Patent Act. However, the courts through a number of case law tried to aid what constitutes invention. [United Mattress Machinery Co. v. Handy Button Machine Co., 207 F.2d 1, 5 (3d Cir. Del. 1953)].
Invention is defined to include "any new and useful process, machine, manufacture or composition of matter and thus is broad enough to include method patents." [Cardiac Pacemakers, Inc. v. St. Jude Med., Inc., 576 F.3d 1348, 1362 (Fed. Cir. 2009)].