Beat and spanked... and there wasn't a clear distinction in my home either.
But if you asked many who spank where the line is, their line for what is an acceptable spanking may be VERY different that yours.
Their "spanking" may be your "beating". Or vice versa.
In my father's view a spanking wasn't effective unless it had elicited some response from the victim.
And I'm aware that this is common with most people who spank.
However, after my mother's death, when I was 7, I became pretty emotionally shut down... and any sort of violence completely shut me off. Thus I was mute and completely non-reactive even thought I felt it all.
At various times I was "spanked" by hand, with belts (both thin and thick, including the buckle ends), with wire cords, with green hickory switches that still had sharp spines where the side twigs were cut away that broke the skin and caused bleeding, with that old thick yellowy latex rubber surgical tubing(good god that shit was wicked), etc.
And those were the "spankings", as in lashing to my ass for a "reason"... not the spontaneous beatings that seemed to happen for no real reason that I could discern or if I could discern the reason at least one I could not understand, and probably included getting hit in the face or choked.
And while I don't know many people who were beat like me, as in hit/punched... most of the people I grew up with, and many of my friends over the years, have all shared stories of the implements that they were "spanked" with, and how often marks including bruises were left behind.
I'm pretty sure that a good portion of the time "spanking" crosses the line.