"rickman" wrote in message ...

The term "amateur" is often applied to people who have obtained a license
to use radio equipment for communications. Is this term inclusive of those
who don't obtain a license but use receivers for various uses?

I have been looking into design of receivers in the LF to ELF frequency
ranges. Is this part of "amateur" radio?

No.
My understanding of "amateur radio" is having a license to transmit on
"amateur" bands.
Receiving, studying receivers, building receivers, etc. does not require a
license....at least in civilized countries