ärˈsfenəˌmēn, -_mə̇n noun
( -s )
Etymology: International Scientific Vocabulary ars- + phenamine
: a light-yellow toxic hygroscopic powder C 12 H 12 As 2 N 2 O 2 .2HCl.2H 2 O derived from arsenobenzene that was formerly used in the treatment of spirochetal diseases (as syphilis, relapsing fever) — see neoarsphenamine