Cant think of a sutta to quote this from so from memory.
uusually when the Buddha uses the term Boddhisatta it is followed with destined for enlightenment as in
when I was an unenlightened Bodhisatta destined for enlightenment
so I would imagine in the theravadan context Bodhi is used in Bodhisatta to denote the end of the path that being is on??? almost like a sotapana is two kinds of persons those on the path to and those who are fully sotapanas, maybe a Bodhisattva is someone who is on one of the first three levels