Sailing ship
A sailing ship is a big boat with sails attached to the mast, to catch the wind. The wind pushes the boat along. A sailing ship had a rig of at least three masts, square rigged.
Sailing ships have been used since prehistoric times. They were greatly improved around the 15th century, and were the main kind of ship until the middle 19th century. They were very important for trade and war. All large boats became known as "ships", so when steam power was invented people talked about "steam ships" to distinguish them from "sailing ships".
Small boats with sails are called "yachts" or sailboats. They are used today for leisure activities.