Monseigneur \Mon`sei`gneur"\, n.; pl. {Messeigneurs}. [F., fr.
mon my + seigneur lord, L. senior older. See {Senior}, and
cf. {Monsieur}.]
My lord; -- a title in France of a person of high birth or
rank; as, Monseigneur the Prince, or Monseigneur the
Archibishop. It was given, specifically, to the dauphin,
before the Revolution of 1789. (Abbrev. Mgr.)
[1913 Webster]