Forms of verbal address between officers and soldiers.

[Maiorianus]

As an aside, the word patronus is said to have become padrino in Italian, which is used to describe a mafia godfather.

I agree with the relevance of the client system in the Roman Army, as well as what you say about the social classes in Rome. I still think that the class difference between a centurion and a soldier was largely non-existant, especially in the Republican period, so the use of a word like dominus strikes me as too strong. Especially for the Republican Romans who, with their founding myths about killing kings and tyrants, were quite restrained in open displays of power until late in the Republic.


As an aside, padrino comes from the late Latin patrinus (small father), which was (and still is) the proper term for the godfather at a baptism, long before Mafia was around...