Yours, Etc.: Origins and Uses of 8 Sign-Offs
c.1600, "a name," from Middle French nomenclature (16c.), from Latin nomenclatura "calling of names," from nomenclator "namer," from nomen "name" (see name (n.)) + calator "caller, crier," from calare "call out" (see claim (v.)).
Nomenclator in Rome was the title of a steward whose job was to announce visitors, and also of a prompter who helped a stumping politician recall names and pet causes of his constituents. Meaning "list or catalogue of names" first attested 1630s; that of "system of naming" is from 1660s; sense of "terminology of a science" is from 1789.
nomenclature no·men·cla·ture (nō'mən-klā'chər, nō-měn'klə-)
A system of names used in a science, as of anatomical structures or biological organisms.