Rita sent a great question today. She wanted to know the correct way to make combined titles plural when using a slash.
Is it singer/producers? Or singers/producers? Singer/songwriters? Or singers/songwriters?
The answer is this: Make it plural just once–not twice. These are correct:
Singer/songwriters: Both singer/songwriters received a Grammy.
Singer/producers: It’s an impressive line-up of singer-producers.
Actor-directors: The three actor-directors will compete for the Oscar.
Secretary-treasurers: The secretary-treasurers both serve in January so that the transition is smooth.
Editor/publishers: Many editor/publishers run their own presses.
Notice that I used both the slash (/) and the hyphen (-) for the combined titles. Both are correct. To make matters even more complex, the slash has another name: diagonal.
Although slashes and diagonals are perfect for combined titles such as secretary/treasurer, they are used far too often as substitutes for the words and and or. Eden wrote today asking which was correct: Dear Sir/Madam or Dear SirMadam. Neither! This is correct:
Dear Sir or Madam:
No one has the combined title Sir/Madam. And to expect the reader to translate the slash into the word or is simply lazy.
For combined titles, use the slash or the hyphen, which are standard. But when you mean and or or, spell out the word you intend.