ODM2 Variable Name Controlled Vocabulary ODM2 Working Group A vocabulary for describing the name of Variables. Nitrogen, nitrite (NO2) + nitrate (NO3) Nitrite (NO2) + Nitrate (NO3) Nitrogen Originally from the CUAHSI HIS VariableNameCV. See: http://his.cuahsi.org/mastercvreg/edit_cv11.aspx?tbl=VariableNameCV.