The term "Emo" is used as counterculture; it is an abreviation of the word "emotional". Emo it's defining not only an attitude, but also a fashion that are coming from emocore (emo music).Emocore is a combination between hardcore and punk music which was very popular in Washington DC in the late 80's. The emo culture continued to develop between '90 and '00, reaching the height of its popularity today.
However, the term emo is very different. If you claim "emo" were to mean "emotional" it then becomes an completely wrong word.