Arc the language hasn't been officially updated in 4 years. All names have been used at some point - it's not realistic to expect them to be truly unique.
Taking a look at it from a different angle, even in the case of the legal framework for names - trademark - having Arc the language and Arc the VM thing would be fine.
The truth is, if you don't want people to collide with your name, picking a 3 letter common word probably isn't the way to do it.
Names are hard. :/
I just found out about this language thanks to the link.
More importantly, according to the TIOBE index, Arc programming language apparently isn't one of the 50 most popular languages.
http://www.tiobe.com/index.php/content/paperinfo/tpci/index....
I'm pretty sure the heat death of the universe will occur before all names are used.