What Is the Plural Form of the Titles Sir and Madam If Written in Plural Form?
According to both the Collins and Merriam-Webster English dictionaries, the correct plural term for sir is sirs, and the correct plural term for madam is madams. It should be noted however, that if the title "madams" is used without any corresponding names as a form of polite address then "mesdames" is the correct term to use if addressing several ladies and names.
While there is little confusion over the use of the term "sirs," the word "mesdames" may appear strange to native English users. Madams is also considered a viable alternative in this instance, and ladies is also an acceptable plural term for multiple women that may individually be referred to as madam or ma'am.