ODM2 Variable Name Controlled Vocabulary ODM2 Working Group A vocabulary for describing the name of Variables. n-alkane, C20 C20 alkane, normal (i.e. straight-chain) isomer, common name: n-Icosane, formula : C20H42. Synonyms: didecyl, eicosane. Originally from the CUAHSI HIS VariableNameCV. See: http://his.cuahsi.org/mastercvreg/edit_cv11.aspx?tbl=VariableNameCV.