A hammock is a sling made of fabric, rope, or netting, suspended between two points, used for swinging, sleeping, or resting. It normally consists of one or more cloth panels, or a woven network of twine or thin rope stretched with ropes between two firm anchor points such as trees or posts. Hammocks were developed by native inhabitants of Central and South America for sleeping. Later, they were used aboard ships by sailors to enable comfort and maximize available space, and by explorers or soldiers traveling in wooded regions. Today they are popular around the world for relaxation; they are also used as a lightweight bed on camping trips. The hammock is often seen as symbol of summer, leisure, relaxation and simple, easy living.
Source:
http://en.wikipedia.org/wiki/Hammock
