why are bachelor/ette parties called “stag/hen dos”? :’)
Okay, I delved into the etymology here, and as is often the case, didn't come up with a definitive answer! But here it goes:
So it seems, according to the Oxford English Dictionary, "stag" has been used for male of the species for a while (and for various other random things other than a male deer!). So it is just a way of saying a party with lots of men. In the US, it used to be a word for a man who went to an event without a female partner (to go "stag").
There's also a note that "stag" could mean a castrated male, so I suppose it could be a coarse way of saying that a man about to be married is about to be effectively castrated. Cos you know, misogyny!
Hen party is slightly easier, as the word "hen" has been used since the 14th century to denote a woman or wife, and the use of "hen party" to mean a party where only women attended was found to be in use in the late 1800s.
Both terms seems to have entered common usage to mean the party before a wedding for the groom and bride a lot later than I thought, according to the OED: "stag party" in 1915, and "hen party" in 1965.
"Bachelorette" is a specifically North American term, never to be heard across the Atlantic, and to be honest, here in the UK we don't use "bachelor" that much, either, not for men (at least I don't hear it much). For animals, and for one of the undergraduate degrees you can get at university.
For me, hearing the terms "bachelor/bachelorette party" sounds considerably more sedate and posh than a "stag do/hen do" which is often raucous, with lots of drinking involved (not too many crazy, cult-leader nans, though!).