The open flame ones are called torches too - we tell what is meant from the context.

I know what you mean about things sounding funny. Here in Oz, thongs are a sort of footwear (what we call flip-flops). In the UK it's another name for a dodgy sort of G-string (at least when it's something being worn). Even after 15 years here, I still giggle when people talk about wearing thongs!