I admit, I'm a little bit confused between headphones and headset, I even used the two interchangeably. But that was before and now that I know how they differ from each other, I just wanted to share the knowledge.
As far as I know, hopefully I am right, headphones is mainly used in listening to music. It has a minature speakers which is known as driver and transducers and receivers and receiver elements.
Headset in the other hand, can be used for listening and talking on the phone. Like headphones, a miniature speakers are present in headset but a single one and the microphone acts as the transducers.