So lime and lemon are the same word?
There have been a few discussions about this before, and it can get a bit complicated. If you google this
site:duolingo.com limão lime lemon
I'm sure you will find them.
Does Portuguese use "lima" (which is what word-reference gives as a translation?
European Portuguese uses "lima" for "lime" and "limão" for "lemon". Brazilian Portuguese uses "limão" for both.
That explain why they don't always get my caipirinha right...
Interesting. That makes things a tiny bit easier then!