Very simply, they are two characterizations of how one relates to the outside world. An introvert tends to remain "in" oneself. In other words, if a problem were to arise, that person might open a book or pace back and forth to come to a solution.
An extrovert is exactly the opposite: the extrovert experiences the world more through contact with others and shared experience than through self examination or study. If the same problem were to come about for an extrovert, they would more than just likely find someone to help.
An extrovert is exactly the opposite: the extrovert experiences the world more through contact with others and shared experience than through self examination or study. If the same problem were to come about for an extrovert, they would more than just likely find someone to help.