Pop music may be distinguished from classical or art music and from folk music, but since the term spans many rock, hip hop, rhythm and blues (R&B), country, dance and operatic pop acts, it is reasonable to say that pop music is a loosely defined category.
Exclusive partner, more commonly known as an EP (pronounced E-P), is the stage in a relationship in which you have full exclusivity with another person, with the intention of pursuing a relationship in the near future. However, this other person is not your boyfriend/girlfriend yet.
An instrumental is a musical composition or recording without lyrics, or singing, although it might include some inarticulate vocal input; the music is primarily or exclusively produced by musical instruments.