Yes, but if I browse through my MorphOS setup (startup's etc.) I'll find - of course - stuff like "Kickstart" or "Workbench" all over, which is needed for backwards compability. Both names are copyrighted, though. Same is/might be true for AROS. Does ReactOS have a "windows32.dll" (or similar)? :-)
You can't copyright a name. You can trademark it. However, trademarking a name does not prevent all use of it, just (in general terms) marketing usage and usage that might cause consumer confusion with the trademarked product.
