Cirno's name is pretty unique among fairy names, perhaps because it came before the pattern was established from lily white onwards, but it still follows the general theme of fairy names coming from western words. In Cirno's case, it's a corruption of 'Chill' to 'Chiru'.
Probably the biggest hint to this is Chirumiru, the old ad parody song, because it's based on rhyming Chill with Mil(k).
Ok, I'm not sure if this pic is legit traditional media or faux traditional media that looks almost real. Is there any infor regarding this particular artwork?