1. A corpulent usually southern person who often spends there time at assorted arbys, filling there beak like noise hole with delicious sandwiches.
2. An enormous animal of the avian variety which oft terrorizes local arby restaurants, preying on the young, fat, and defenseless.
they were all out of fries, there were, like, seven arbytrosses in there
skrwaaaawwwwwwwww, quoth the arbytross