Ladies is the plural form of lady, so the apostrophe goes to the right - ladies'. If you are wondering why we don't write ladies's, it is because ladies is one of the exceptions, along with girls', parents', … Having heard the phrase, faint heart never won fair lady for the third time in very short span, i'm determined to find out its origin.

I have always tried to understand the use of the word handsome in letter to a lady friend, but refrained from doing so, because i didn't know whether the word would be a thoughtful gesture or insulting. For work-place specific gender-neutral politically-correct terms refer to the answer by @third-news. Otherwise, as elliot frisch has suggested, lady is the term you want. But in my opinion, if you're …