I suspect "person of legal age" is the outlier to the word "adult". See also the word adulterated — "to be made impure." So adultery fits in that context.

The word husband comes from husbandry, which means the care and maintenance of livestock. Roll that one around in your head a bit. And the word bride originally meant restraint... typically in the word unbridled which means unrestrained. Meanwhile, a bride is someone who has traditionally shown restraint for close to 2 decades (not having sex).

Furthermore, girl used to just mean child and it didn't mean a female one, you just called a group of children "girls" instead of "kids." Makes you wonder, then, why most people would address them as "you guys".

Funny how words change over time. No sarcasm here. Genuinely interesting.