Easton's Bible Dictionary
The old plural form of this Hebrew word is 'Adonai . From a superstitious reverence for the name "Jehovah," the Jews, in reading their Scriptures, whenever that name occurred, always pronounced it 'Adonai .
These dictionary topics are from M.G. Easton M.A., D.D., Illustrated Bible Dictionary, Third Edition, published by Thomas Nelson, 1897. Public Domain.
Easton, Matthew George. Entry for 'Lord'. Easton's Bible Dictionary. https://www.studylight.org/dictionaries/eng/ebd/l/lord.html. 1897.