Earphones
These are the most common, used and abused speakers that probably every one has owned at some point in their life. Probably they are on right now while reading this. These are tiny speakers, with lesser power and impedance. They fit in right at the opening of the ear, as their radius is more or less the size of the opening. Plus they too are covered with padding of either cloth or rubber. These don’t offer as good sound quality as the aforementioned types, though their ease of use and portability make them popular amongst music lovers who need music on while eating, sleeping, jogging, writing an exam etc.
In-ear or Canal phones
A specific type of earphones is canal phones. These are different as in they actually fit right into the ear canal, with the help of their unique construction: a rubber sleeve protrusion is attached on the earpiece that acts as a ear plug, thus blocking out external noise. Another advantage is the ergonomical value of these earphones — they are very comfortable. Since they fit into the ear directly it isn’t required to attach them to any clip or headband of sorts.
The other special kinds are Surround headphones, which emulate surround sound in your head with just regular stereo headphones, at least on the exterior. Inside they are a completely different story, with multiple drivers and placement. Some models come with an external decoder, while some have the technology built in. They are popular with gamers. Eg. Razer Baraccuda, Creative Headphones HQ-2300D
These are just nomenclatures though. There are various types of sub-categories that you can read about here.
very useful,but could not get details on wireless headphones 
