The oboe is a long, conical instrument that has two reeds. As the reeds vibrate they produce a rich sound.
The oboe was developed in the 17th Century from an instrument called the shawm. It differs from a clarinet because the oboe has two reeds; a clarinet has one.
The English horn is similar to the oboe, but produces a different sound because it is slightly longer and has a bell rather than conical opening at the end.