As the data base says, Dominic means “(property) of the Lord”, but also “born on a Sunday”, as Sunday is considered the day “belonging to the Lord”. Now my question has three parts: a) When did the name Domikus first turn up? (I suppose originally it was a Christian name in the very sense, indicating: This child is the Lord’s property, so hands off, all you dark powers …) b) When did the Christians start giving this name to a child born on a Sunday? What would be the sources to tell us? c) What was the Latin term for “Sunday”? – “dies domenikus”? “dies dominicus”? “domenica”? When was “Day of the Lord” first used as a term for “Sunday”? Because in the New Testament (like in the Hebrew bible), as far as I can see, “Day of the Lord” has a different meaning: the day, when Christ will return, judgement day.