Lan can be either used as a girls name meaning Orchid in Chinese or as a boys name, meaning 1. Powerful Ruler(French) 2. From the Field(French) 3. Long hill, ridge(Old English).
Lan(M):
http://www.babynamespedia.com/meaning/Lan/mLan(F):
http://www.babynamespedia.com/meaning/Lan/fIts a unisex name when you look at it in a way. But, the origins differ and you generally hear it as a boys name. To be honest, I always thought Lan sounded boyish.
Blame the Chinese for making it a girls name as well.
I generally use that site to find nice names and such. Or to find out what they mean. And in the other cases, to find names that would fit a character well. I mostly use Old, Celtic, Latin and Japanese names.