okay. word origins aside -
. . . .
physically. . . . in USA terminology . . .
"to grill" is exposing the "target" - supported on some "structure" - to heat from the bottom, heat intensity 'undefined'
"to broil" is exposing the "target" - supported on some "structure" - to heat from above, heat intensity 'undefined'
"BBQ" is a real can of worms even in US parlance. my take is low heat, usually indirect, long long cooking time.
basically sous vide without water or bag . . .
high volume operation often employ a vertically rotating chain arrangement - others simple flat racks.
definite worm can . . . .
so,,,, how does one classify Greek vertical rotisserie meats ala ''shiskabob' . . . and all fifty spellings thereof . . .
or a USA "ox roast" - on a huge rotating horizontal spit over open coals . . .
or "roasted chicken" on a rotating spit, on a vertically oriented rotating conveyor rack, exposed to heat "from the side" . . .
((in Germany, this was/is "Wiener Wald" style....if you need an image....))
should we be concerned, for those other than quaint historians . . . with Shakespearean definitions, or real live today meanings of "words?"
just as US "All Purpose Flour" is UK "Plain Flour" and US "Bread Flour" is "Strong Flour" . . .
different words for the same thing.
the same cooking "methods" identified by different "words" - which is the point.
the etymological word origin(s) (did I get that spelling right.....) is not remotely meaningful as to how the "words" are used today.