cIOS either stands for "Custom Input/Output System" or "Custom Internal Operating System". cIOS is quite simply a modified/patchedNintendo Wii system IOS. by which we can run our own code (homebrew).
Person #1: What's your cIOS version ??
Person #2: it's cIOS Rev14.
Stands for Cheer It On. Which is what people with slow internet connections do to the new revolving circle for Netflixstreaming.
So, Sam, I heard you saying, "Come on, take some more bandwidth from somebody and finish revolving already!" last night.
Yeah, I was doing my CIO thing to speed up my movie.