Well, I didn't know, either, but if I'd had to guess I would have said it came from one of the native Australian languages.
Surprisingly, however, this doesn't seem to be the case. There are, of course, many native Australian words that mean didgeridoo, it's just that none of them bear any resemblance to the word didgeridoo. Favourites of mine include Gunbarrk, lipirra and ngarrriralkpwina.
So who made up the word didgeridoo?
There's more than one theory about that. One is that it's an imitation by an English-speaker of the sound a didgeridoo makes.
What do you think?
Personally, I think I'd have put more wow whirr and buzz sounds into an imitation of a didgeridoo - called it a buzzwerwhirrer, perhaps - but didgeridoo isn't an impossibly bad attempt.
On the whole, though, I prefer the rival explanation of the word didgeridoo's derivation.
But that's mostly because it's just so utterly unexpected and bizarre.
Word To Use Today: didgeridoo. This word first appeared in print in 1908 in the Hamilton Spectator, and it was noted soon afterwards that the instrument produced just one sound, which was written down didjerry, didgerry, didjerry. I can't deny this is quite convincing.
However, the word didgeridoo just might come from the Irish Gaelic phrases dúdaire dubh or dúidire dúth, which might mean anything from native trumpeter to black long-necked person, eavesdropper, or chain smoker.
I think this may be a case where ignorance really is bliss.