Sailing specifically refers to the sport of using wind to power sails and propel the boat forward (rather than engines). Unlike windsurfing and surfing, the sport takes place in an enclosed boat rather than on a board.
Today it is mostly a recreational activity. There are two types of sailing – racing and cruising. Racing is the branch of yachting you will recognise from the Olympics, however cruising is probably what most people would enjoy on their holidays or on the weekends.