Any good literature on the topic of the Zulu War 1879 gives us names of the different ibutho involved in the battles, names such as uKhandempemvu, uMxapho, uDududu and iNgobamakhosi. Men were so identified by their ibutho that some of them were known by the name of their ibutho years and years after the war. But what do they mean? How were these names selected and given to the different ibutho that were formed?
I'm not at home at the moment, but the book I want to reference is Ian Knight's Anatomy of the Zulu Army. John Laband's Rise and Fall of the Zulu Kingdom is also excellent, but it's a general history without all the names in one place, I believe. Anyway, I'll work from memory and check/correct/expand upon my answer when I get home.
Zulu regiments were named during the kleza, the original muster where boys in their late teens from all over the kingdom came together for the first time to form a new regiment. Some of the names are pretty easily understood: uThulwana --very loosely translated as The Chieftains-- was famously a regiment with an unusual number of princes and the heirs to northern clan barons among them; King Cetshwayo, for example, was an uThulwana. The iNgobamakhosi, The Humblers of Kings, was the large and boisterous generation twenty years younger than the uThulwana who competed with the Chieftains for fame and Royal patronage. Their name is literally saying they're going to take those old nobles down a peg or two. Other names like Khandempemvu (The Red Needles Sharpened at Both Ends) and the uVe (Flycatcher birds) drew their names from nature, but the story behind it is lost. Still others, the DuDuDu most prominently, we're literally named for their most famous war song.
The other names that come back to me, The Young Mambas, The Stumbling Blocks, The Frost, The Mongrels, and so on, all have an air of 'you had to be there' among them. Basically, if you ever went to summer camp or a school out of town and you and your friends gave your gang a nickname that was difficult to explain to outsiders as your communal identify, you know how these things develop out of nothing.
EDIT: I'm home now with the book in front of me. The uThulwana were literally named after a BaSotho chief named Thulare, which seems to be a unique circumstance in amabutho naming. I did say it was a very loose translation to call them The Chieftains, but I seem to have gone too far there. I also misremembered the uKhandempemvu (The Head with Black and White Markings) as the uMcijo, a nickname for the same group meaning the Red Needle Pointed at Both Ends.