flash of genius rule
flash-of-genius rule. Patents. The now-defunct principle that a device is not patentable if it was invented as the result of trial and error rather than a “flash of creative genius.” • The rule, which takes its name from language in Cuno Engineering Corp. v. Automatic Devices Corp., 314 U.S. 84, 91, 62 S.Ct. 37, 41 (1941), was legislatively overturned in 1952. 35 USCA § 103.