Elis Regina.
The title says “Musicians,” and Joni is one of the only women mentioned so far who is an actual musician and composer in addition to being a singer.
Almost all of the “divas” mentioned here are singers only, not musicians or songwriters.
I’m not sure that I can actually respond to that in a way that won’t get me warned.
At the risk of alienating the entire southern half of the US…
Reba?
Anne Sophie-Mutter
is certainly a talented female musician, but she’s a violinist, not a singer. I don’t think I’ve ever heard the term “diva” applied to anyone other than a singer.
Perhaps thinking of Anne Sofie Von Otter?
Sondra Prill
I see your Joni Mitchell and raise you Hiromi Uehara.
(Though she’s a pianist, not a singer. But you said “musician”.)
Are singers musicians? 'Cause I don’t think so.
My two degrees in music from the music department at a top tier university, my teaching position in the music department at a top tier university, my two decades of dedication and hard work at refining my craft in the musical arts, and the basic dictates of language would tend to disagree with you.
Would you care to actually make an argument rather than simply posting your unsupported and ignorant opinion?
There’s many female singers that I like, but the only one that puts the image of a “diva” in my head would be Gaia Riva. Other than that, so far as I am aware, she’s not particularly famous nor known.
As both an instrumentalist and a singer, I will wholeheartedly say that, yes, singers are musicians. The human voice is an instrument, to be used for good or ill.
Watch this and tell me that Floor Jansen (the female singer) is not a musician:
I submit Clare Torry’s incomparable performance in The Great Gig in the Sky as a piece of evidence that (some) singers are musicians.
I must admit, that’s an astounding piece of work.
I saw a documentary on the making of DSOTM and she was given free reign to sing whatever she felt was appropriate, and she came out of the session feeling disappointed with her recording! If you can believe it.
Here’s an interesting interview with Clare.
Leaffan - I want to point out that, whether you know it or not, this is an extremely rude thing to say to singers. You’re questioning/walking right past their craft. If you kinda know this, and were saying it for snark value, well, that would not be nice. If you really didn’t understand that singers are musicians, well, please note that they are.
This is kinda like looking at one athlete from one ethnic group and saying “they work hard” and another from another ethnic group and saying “wow, they have natural talent.”
It’s also linguistically incoherent, unless we’re using some esoteric definition of “musician” that I’m not aware of.
If this was being discussed sincerely by non-music folks, I would assume that there is a thought that says “Musician = someone who makes music using an instrument/object” vs. “Musician = someone who makes music.”
Just to be clear: it’s the second one, folks! 
It’s kind of like those 'leventy-billion drummer jokes. I have a drummer friend - brilliant musician - who loves to invoke the sign he saw at a park: “No musicians or drummers.”
Cute, but…sigh.
I think people who say what Leaffan said may be thinking along the lines of “Singing doesn’t make you a musician: everybody does that—at church, in the shower, at summer camp…”
But yeah, a professional singer, of whom the word “diva” is an appropriate description, would definitely be a musician.
I notice that over in the recently-revived thread Are the Beatles overrated as musicians? some, but not all, of the replies are addressing only the Beatles’ instrumental abilities.