useful
useful a. 实用的；有用的；有助益的 泛指满足特定用途的能力，可指现在和将来的用途。在专利法中，一项发明的「有用」是指它可使用于所设定的目的，并对社会产生有益的效果，而且不违背法律、道德和公共政策。在美国，宪法和国会授予某项发明以垄断的权利，就是以其实用性作为基本交换条件，即公众可以从中获益。
USEFUL
useful
useful, adj. Patents. (Of an invention) having a practical application. [Cases: Patents 46. C.J.S. Patents § 59.] “[M]ere curiosities of invention, which do not have any intelligent purpose, are not useful in a patentable sense.” Roger Sherman Hoar, Patent Tactics and the Law 37 (3d ed. 1950). “When applied to a machine, ‘useful’ means that