nomenclature (n.) Look up nomenclature at Dictionary.com
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" (from PIE root *kele- (2) "to shout").

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.