EMO is...

Emo is generally said to have started with DC bands like Embrace (Ian
MacKaye's band after Minor Threat and before Fugazi) and Rites of
Spring (Guy Picciotto's band also before Fugazi), but is in no way
limited to them, around '85. The sound was basically a slower more
emotional (hence the name "emo") post- version of hardcore. The vocals
are usually sung in "whiny" (for lack of a better word) sort of way.