What is the base meaning of opposite?

dictionary.com defines opposite as:

situated, placed, or lying face to face with something else or each other, or in corresponding positions with relation to an intervening line, space, or thing:
opposite ends of a room.
2.
contrary or radically different in some respect common to both, as in nature, qualities, direction, result, or significance; opposed:
opposite sides in a controversy; opposite directions.
3.
being the other of two related or corresponding things:
friendly with many members of the opposite sex.