You use overseas to describe things that involve or are in foreign countries, usually across a sea or an ocean. He has returned to South Africa from his long overseas trip. overseas trade figures. = foreign Overseas is also an adverb. If you're staying for more than three months or working overseas, a full 10-year passport is required = abroad
An overseas student or visitor comes from a foreign country, usually across a sea or an ocean. Every year nine million overseas visitors come to London. = foreign. coming from, existing in, or happening in a foreign country that is across the sea home