What's the proper terminology for nebula clouds? I'm writing a research paper over outer space (yeah, yeah, broad topic) and I'm wondering what the proper terminology for nebula clouds is.  This is an excerpt from my paper showing how I'm going to use the term:  "Outer space is the host of all the types of stars and galaxies and a lot of other interesting phenomena, such as black holes, supernovas, and ________."  Long story short, would I use "nebula clouds" or "nebulae"?
"nebula clouds" sound a little bit redundant, because, is there any nebula that is not a cloud?

I would stick to "nebulae". (And if you want to be consistent, you should be writing "supernovae" too).

I am not an expert on this topic, but I have never seen any use of "nebula cloud" before.