ˌdekəmə̇ˈthōnēəm noun
( -s )
Etymology: deca- + methonium
: the bivalent substituted ammonium ion [(CH 3 ) 3 N(CH 2 ) 10 NCCH 3 ) 3 ] ++ derived by methylation of deca-methylene-diamine ; also : any salt containing this ion (as the iodide or bromide used as a muscle relaxant)