I have noticed that ArtScroll usually translates the shem of Adnus (Adonoy) as My Lord. Other translations of the Tenakh and Siddur use "Lord" or "O Lord." There are some pesukim that cannot be translated as ArtScroll usually does and then they switch to the plain Lord or even HaShem. What should be the correct English translation? Rabbeinu Bachya seems to like "Lord of Lords." I guess it depends on whether you consider the last letter to be the possessive or an intrinsic part of the shem.
The unique pronunciation with a kamatz under the nun suggest that it is not simply translated as equivalent to the plural "adonai"("my lords") which has a patach (as is the case, e.g. by "elokim"-"elohim" [powers]). Nonetheless, that is the word which it most closely resembles.
The Maharal, in a different context, indicates that a plural is used to convey a sense of limitlessness. As such, the sense would seem to be "my L-rd above all lords".