The funny thing is that in most ham radio usage, the "high frequency bands" are actually about as low a frequency as most people will ever use. I don't think I've come across anything about low and medium frequencies except in reference materials. People generally use "high frequency", "very high frequency", or "ultra high frequency".

AM radio is medium frequency.

Radio clocks are low frequency.

I’ve found myself explaining that to people a few times. Lower frequencies are also used to communicate with submarines since they propagate better through water.

I’m guessing that when radio first came out frequencies were lower, though I don’t have any facts there.

“Shortwave radio” is another one that’s confusing term these days for the same reason.