What does Three Sheets to the Wind Mean?

Three sheets to the wind, describes something or someone that is out of control. The term originated due the use of ropes that are located at the corner of sails, used on ships, called ‘sheets’. If these ropes weren’t set properly, the sails would start to flutter in the wind, which caused the ship to get out of control. The term is used frequently, when you see someone that is drunk, and you respond with ‘Wow, he/she is three sheets to the wind.’