ˈbekmən-, -ˌmän- noun
Usage: usually capitalized B
Etymology: after Ernst O. Beckmann died 1923 German chemist
: a rearrangement by which a ketoxime [as the oxime (C 6 H 5 ) 2 C:NOH of benzophenone] changes into an amide derivative (as benzanilide) on treatment usually with phosphorus pentachloride or an acid