The trap can be anything from a neighborhood to a single house (aka trap house), and it's where drugs, mostly cocaine cooked into crack, (but any drug really) can be sold. The term originated in Atlanta as far as I know, and a lot of rappers who started out in the business associate it very heavily either with inspiration for their music or their lyrical style. T.I. was probably the first and most prominent rapper to give rise to the term, with 2Chainz being the most popular proponent of trap and trap music currently. To add more confusion, I believe it's also a form of electronic music with a specific BPM for the bass, and can be distinguished from dubstep and house by its heavy bass line and more minimal melodies (or whatever you'd call it).
[–]ryan1074 21 points 4 years ago
A trap house is a older style home with one way in and one way out (the front door). It is reserved as a house where you can typically buy crack or any other type of drug. But it is referred to a trap house because as drug dealers and they are in an illegal business they have no recourse if they are robbed, i.e. if some one busts down the front door at gun point to take their drugs and money they are "trapped" in their own homes and most likely the place where they will be murdered by aforementioned unknown assailant. Vice is actually doing a documentary about trap music. Its pretty good and might answer any more questions you might have. I having watched the majority of it myself and its pretty good altho some of these interviewees seem a little full of shit but what are you going to do?