If you study abroad in your junior year of college, you are going to school in another country. Use abroad when you are talking about going to or from a place across an ocean.
Abroad really just means in a different country, but it is almost always used interchangeably with "overseas." You almost never hear an American say, "She lives abroad; she's studying in Canada." You might be eager to take a trip abroad. If so, get your passport ready. They won't let you board a plane going abroad without one.
