Is there a difference between Ms. and Miss? To me, Ms. is just an abbreviation of Miss, and pronounced the same way. I’ve had a discussion about this with a person who absolutely insists that there is a difference between the two. Any input from a grammarian or linguist would be much appreciated 
Ms. is pronounced miz, not miss. They are absolutely different in sound.
And Ms. is absolutely not an abbreviation of miss. It was devised from scratch as an analog of Mr. so that the marriage status of the woman was not an issue.
Then what about Mrs.?
Mrs. (pronounced like “missus”) indicates the woman is married (or was married). Miss means she is single. Ms. means she is not specifying her marriage status with her title, rather like Mr. for men.
Wow, I was taught in elementary school that Ms. was an abbreviation of Miss.
WHAT ELSE HAVE THEY LIED TO ME ABOUT?
I think that’s where my error lies 
Everything.
In Southern culture, Miss (First Name) is commonly used by both kids and some adults as a form of respect. I grew up using it especially for my friend’s mothers who were married.
Right, I was thinking about that after I posted; I had only been thinking about it in combination with the surname.
Kids these days. <shakes heads>
Back before 1970 or so, you addressed a man as Mr., but you addressed a woman as either Miss or Mrs., depending on whether she was married or not.
The question was what if you didn’t know the marital status? In a social context, you usually did, of course, but what about in a business context?
The proper etiquette was: if you didn’t know, you used “Miss,” because that implied the woman was younger and thus was very flattering to her. See if you can spot the sexism in that sentence.
(Oh, and a married women was properly addressed as “Mrs. John Smith.” If she was a widow or <gasp> divorced, her maiden name was included: “Mrs. Jones Smith”)
Some women objected to this, pointing out that it shouldn’t matter if they were married or not, especially in a business context. In line with the objection to calling grown women girls, women coined the term “Ms.” to be a form of address where her marital status was not an issue.
The coinage was derided by language purists. But despite them, it caught on. It filled a need: if you were writing to a woman in a business context, you often didn’t know their marital status (and it didn’t matter). Write “Miss,” to a “Mrs.” or “Mrs.” to a “Miss” could be awkward. “Ms” is now the normal way to address a woman, the same was you’d address a man as “Mr.” whether he was married or not.
I wonder, how old are the people who have corrected me on the proper usage of Ms. vs. Miss? In general, are you old enough to remember the change or be affected by the usage in some way (i.e. already at work in a business setting)?
Depends on what you mean by when the change happened. It started back in the 1700s and has been used in the US on and off as a marriage-neutral term since 1901, apparently. But no, I’m younger than any of the dates mentioned in that article as times of popularity. (And I do use Ms.)
Exactly what I was gonna post.
It is a fascinating book. Really!
Personally, when I’m addressing a woman of unknown marital status in a business context, I can usually get away with “Dr.”. Or when I’m addressing a man of unknown status. Or when I’m addressing someone of unknown gender. Academia is convenient, that way.
While there were isolated attempts to use “Ms” prior to the 1970s, they never caught on any more than the attempt to use “yeye” as a gender-neutral pronoun did in the 90s. People only talked about it, but it was generally ignored.
By 1970 or so, the women’s movement was able to make the argument for the usage. The idea of particular phrases being sexist and offensive grew out of their efforts and people began to accept the need for the term. By about 1980, it was standard.
I do remember the debate about the change back in the 70s. People argued that there as no reason to coin a new term and that the usage of “Miss” for a woman whose marital status was unknown had a long and proud history drone drone drone. And, of course, they claimed it was a compliment, like calling the women working in your office “girls.”
Ultimately, the “defenders of language” lost because the term was so useful.
In addition, you have to say the “z” for a really long time, to make it clear that you’re not saying “miss.” Miizzzzzzzzz.
I thought the standard pronunciation was “məz”, not “miz”.
I still find that “Miss” is used as an address instead of “Ms.” or even “Mrs.” After all, you never (in the USA) hear anyone say, “Excuse me, missus” or “Excuse me, Ms.” It’s “Excuse me, miss.” It complements “Excuse me, sir.” The use of “Excuse me, mister,” seems so Leave-it-to-Beaverish.
Up north, perhaps, and the “miss” construction is also common among Spanish-speaking populations. But in the south, the compliment to “Excuse me, sir” is still “Excuse me, ma’am”. It’s interesting that people have simultaneously fled from “Miss” as sounding too young and “Ma’am” as sounding too old.