How does genshin define "Human"???

im almost done fontaines latest archon quest and i was just wondering. Throughout my playthrough of genshin human is thrown around as a general term to describe sentient beings with the only exception being monsters, archons, primordial dragons and the likes but with the fontaine archon quest the oceanids which took on the disguise of humans were refered to as "Human" throughout the quest and even Furina when she is talking to her divine self is refered to as Human but the fact is she isn't and they aren't human they are oceanids. But if the game refers them as human and even a divine archon refers her as human where is the line crossed? Does human not refer to the specific species of homosapiens but a congregation of species with sentience but limited power? But even if that is the case why are some sapient creatures not refered to as human while others are? T

he fontainian residents who are truely oceanids are considered human but other creatures such as perhaps the talking dog and cat Don Quijano and Nana, would they not also be considered Human?