ODM2 Variable Name Controlled Vocabulary ODM2 Working Group A vocabulary for describing the name of Variables. Polycyclic aromatic hydrocarbon, alkyl Polycyclic aromatic hydrocarbon (PAH) having at least one alkyl sidechain (methyl, ethyl or other alkyl group) attached to the aromatic ring structure Originally from the CUAHSI HIS VariableNameCV. See: http://his.cuahsi.org/mastercvreg/edit_cv11.aspx?tbl=VariableNameCV.