"My sister is a firefighter."
Translation:Min syster är brandman.
You could also say brandsoldat if you want to be gender-neutral. Whereas many occupations on -man have changed to a gender-neutral alternative over the year, brandman is still the most common word.
It does mean "fire", but it is usually only used to describe big fires that get out of control. The more common word for fire is "eld".
There's also fyr which I now realise makes sense in the word avfyra=fire (a weapon). But fyr isn't so common (other than the exemples in "See also" on the wiktionary: sätta fyr på; ta fyr; fyra av and the other meaning of the word) so it's probably not worth teaching anyone at this stage/on the Duo course :)
Well, fyr is usually only used to mean "fire" in different constructions as you point out, but the main usage of "fyr" is Lighthouse which is "En fyr" in Swedish. I do not think that any Swedish speaker would look at the word Fyr and think of fire though.
The word "fyr" comes from the greek word pyr which means, or at least meant, "fire".
Yes, of course. I myself would probably only think of en fyr if I heard fyr but I (as a Swede) use fyr in those constructions sometimes and I also hear it sometimes from other people so I thought it's worth pointing out to non natives that it exists :)
In that case I guess pyra is related as well :)
We (germanic speakers) didn't borrow the word from greek. They evolved separately from a common PIE ancestor :)