The newly refurbished OSC forum web site has sparked off some discussions on the OSC_dev mailing list. One interesting note was a reply from Andy W. Schmeder on how OSC should be spelled out correctly:

The short answer is, use “Open Sound Control”. The other form one may encounter is “OpenSound Control”, but we don’t use that anymore. Any additional forms you may encounter are probably unintentional.

I have been using various versions over the years (also including OpenSoundControl), I guess this is then an official answer since Andy is working at CNMAT.