A khopesh sword is a weapon of ancient Egyptian design, dating to at least 1300 BC and perhaps much older.
The khopesh has about 6 inches of handle. The blade extends straight out for about 18 inches, before taking a wicked curve for the last 2 feet. The sword is usually made from either bronze or iron. This design is based upon that of the sickle. But the khopesh sword is sharpened on both sides of the blade, unlike the sickle which only has the inner side sharpened.
The khopesh sword was mainly used by the nobility, even the pharaoh was said to have one. This weapon has also been referred to as the Canaanite sickle sword, which is accurate for the earlier examples, but later khopesh swords were very different from the sickle.
Sources:
Arms and Equipment Guide
http://gemstone.net/etimes/et6/armory.htm
http://www.users.bigpond.com/deeefa/khopesh.html