[Izkata]

It's a simplification of the original icons which both looked like and were called menu icons/buttons, so it makes some sense if you were around long enough:

https://www.theregister.com/on-prem/2010/07/28/samsung-galax...

https://android.gadgethacks.com/how-to/deal-with-broken-hard...

The Samsung one goes up instead of down because that's how it opened on the old Android phones.

I tend to also still call it a menu icon.