We are about to get a new horse at work; when I went out to inspect him I was amused by the fact that he bears a striking resemblance to the black horses used by the nazguls in the LOTR films. Since we most definitely will be renaming him, I thought it would be nice to pay homage to the visual similarities. So… do we know if the Witch King’s horse had a name?
We don’t even know for sure that the Witch King’s horse was actually a horse. It’s assumed that the Nazgul rode horses before the Fords of Bruinen, but given that their steeds after were “fell beasts”, it’s entirely possible that their horses were also of an otherworldly nature.
But no…the only name we really have connected to any of the Nazgul or their accoutrements is Khamul, who was the Nazgul second-in-command.
There’s mention that Sauron raided the Rhohan for horses, and always for black horses so we can assume that they were being used for Nazgul and other “special” agents of his will.
But they were dumb animals not worthy of names. 
Where did you find his name? and, what language is it in? Numenorean? doesn’t sound Elvish, which I suppose makes sense if he got corrupted over to Sauron.
This particular horse is pretty darn dumb, so it would be even more fitting. 
I would really like to give Brego a buddy, though… shame it may not work out.
Incidentally, my apologies for the horrible typo in the OP- I’m aware there’s no “s” on the end of Nazgul. Thank you all for not smacking me around.
He’s mentioned in “Unfinished Tales” I think. Basically he was a Easterling. There’s no real need for a ring wraith to have had an elven name. In fact it’s more likely that the name is Andunic or from the southeast of middle earth. I’ll leave that to the experts to answer better though.
You could always call the horse Fatty Lumpkin is your getting desperate. Or Samwise if it’s none too bright.
No name is attested for any Nazgul’s steed, in Tolkien’s works. However: The horses who played those steeds in the movies probably did have names, and a bit of research might turn up one of them. This does, however, run the risk that the name will end up being something like “Binky”.
Dear Mr. Chronos,
We are writing on behalf of our client, Mr. Terry Pratchett, to ask you to refrain from making dismissive remarks concerning the choice of equestrian names used by our client.
We also note you are using an obvious pseudonym, but don’t have the time 
to check it.
Regards,
Sue, Grabbit and Runne
Are you sure he is not really the Titan of Time? What proof do you base your supposition on?
Jayjay, I question your questioning that the Black Riders road actual Horses. Every indication is that they were bred and trained to work with Nazgul and that at least some of the breeding stock was stolen from Rohan.
Jim
You are correct to question my questioning. I had forgotten that Sauron raided Rohan for black horses.
Of course he did. Black horses are tastier!
I HAVE YOUR NUMBER
Pal o’ Meanos?
Mare Do Wells?
The Witch King himself didn’t have a name. Why would his horse have one?
*“Now, I want you to go to the stable and saddle up the Witch King’s horse.”
“You want me to saddle up which king’s horse?”
“That’s right, and hurry up about it.”
“Now wait a second… does the king’s horse have a name?”
“Well, it’d be a fine thing if he didn’t have a name; of course he has a name!”
“Well, then what is the horse’s name?”
“Witch Horse.”
“The horse we’ve been talking about!”*
I’ve been through the Brown Lands on a Horse with No Name,
It felt good to be off the plane.
In the Mordor you can’t remember your name
cause there ain’t no one for you to give pain.
Bad, bad Leroy Brown
Baddest horse in the whole damn town
Bigger than ol’ King Kong,
Meaner than a junkyard dog
There was a Horse named Sue…
that fell into a burning ring of Fire…
he went down. down, down,
and the flames went higher…
and they burned, burned. burned,
in the ring of fire, the ring of fire…
Did any horses in LotR have magic powers? Why were some so definitely “the fastest” ?
A horse is a horse, of course, of course…
Are they made of chocolate?
The mearas of Rohan were “special”. Not magical, really, but more intelligent, sturdier and faster than normal horses. Shadowfax, Gandalf’s horse, was a meara, as were the horses of the Kings of Rohan (only the kings of Rohan and their offspring could ride the Mearas, besides Gandalf). They were said to be descended from horses that the Vala Oromë brought from Aman.