Mercurius or Hermes = "herald of the gods"
1) a Greek deity called by the Romans Mercurius (Mercury)
2) a certain Christian
Part of Speech: noun proper masculine
Perhaps from G2046; Hermes, the name of the messenger of the Greek deities; also of a Christian: - Hermes, Mercury.
These two sites give similar information, with the definition from several dictionaries and statistics on the use of the word.
Perseus Digital Library
University of Chicago's Logion lexicon
Thayer's dictionary plus other information.
From this site's dictionary (in Italian)
Click on the first column to search for that word as a form of the root Ἑρμῆς; click on the second column to search for that grammatical form of the root Ἑρμῆς; click on the third column to search for that word and grammatical form; click on the total to search for the root Ἑρμῆς.