Fwyaren — Arthur butchers the word, though I can’t profess to be any good at Welsh pronunciation myself. It likely sounds like “voo-arin”. That ‘wy’ diphthong (w and y are both vowels in Welsh) against an ‘a’ is confusing to me. Anyway, it does mean “bramble” though I’m not sure if it specifically can mean a blackberry bramble as well. If Merlin wants it to mean blackberry bramble then it will. This isn’t a Welsh dictionary and he’s a damn wizard, so fuck the rules. Also if you have not picked up on the fact yet that Merlin is Welsh, please do so now.