No offense to anyone ... , I'm not trying to play with " Semantics " !!
BBQ/Grilling Over Direct Heat ; IMHO
It will impart a different taste , as compared to " Roasted Chicken or Routissrie Chiken "
Here's a photo of both: Griiled & Routissrie @ the same time.
I've done both with " Charcoal & Propane " .
I would personally be hard pressed to tell the taste difference (Blind Test) , between one or the other , on any given day; " Roasted or Routissrie "; on
Outdoor Oven / BBQ Grill.
" IMHO " ; You could do the same or better, using a " Convection Oven ", which distributes the heat more evenly during the cooking process....Although , Roustissrie looks way cooler, nothing more !!
Roasting
http://en.wikipedia.org/wiki/Roasting
Routisserie ( Traditionally used method to Cook Larger Cuts of Meats / Whole Pigs /Goats, etc)
http://en.wikipedia.org/wiki/Spit_(cooking_aide)
PAPI