Brussels ("Brussel" in Dutch or "Bruxelles" in French) comes from the Dutch "Broekzele", which in its turn comes from the ancient "Bruocsella". "Bruoc" meant swamp, and "sella" meant chapel. So...
Fastest way is taking the train from the airport to the Brussels South railwaystation (most of the trains that leave from the airport run to that station) The Eurostar terminal is at Brussels South...