1) women's pants without legs, held in position by an elastic waistband (briefs)

2) to place (a person) in a new position of authority with the usual ceremony; to place, fix, (apparatus) in position for use (install)

3) opposite in position or order (reverse)

4) to place a camera, telescope, flag etc in position (set-up)

5) (a person, business etc) not as important, high in position etc as the main person, business etc (subsidiary)