no·men·cla·tor 
(nōmən-klā′tər)
(nōmən-klā′tər)n.
One who assigns names, as in scientific classification.
[Latin nōmenclātor, a slave who accompanied his master to tell him the names of people he met, variant of nōmenculātor : nōmen, name; see n-men- in the Appendix of Indo-European roots + calātor, servant, crier (from calāre, to call; see kelə-2 in the Appendix of Indo-European roots).]