According to one site (http://www.sca.org/heraldry/paul/bl.html
), Bratislav is a variation of teh Russian Briachislav, meaning "buzz-glory." Presumably "Briach" means "buzz" (onomatopoeia?) and "-slav" means "glory" (as noted by Mike http://www.behindthename.com/elements.html
I was shocked to realize that Slav is ultimately derived from the Greek "sklavos" meaning slave (Oxford English Dictionary). It would be interesting to see how "slav," which originally meant something so horrible, eventually came to mean "glory".
PS. Bratislava is also the capital of Slovakia