Pop music genres
Pop comes from popular music. Perhaps this is so obvious, but popular music was the music everybody knew or heard. Sometimes it's linked to money and fame. Some other times it's linked to a special event, but normally it's well-known for wide audiences.
A genre is something bigger than a style. It can be said that a genre is developed through decades and transform into different styles. A style is a group of concised characteristics, in a certain time, with certain bands. So there's hundreds of styles, but only a few genres: Basically, it can be said that there's four big genres: Rock, Pop, Rhythm'n Blues, and Electronic.
Rock genre is a group of different styles were music is aggressive, strong and powerful. It's based on the sound of distorted guitars and powerful lyrics. Bands and artists usually look for fun.
Pop genre groups styles were music is softer than rock, with full-meaning lyrics, normally close to personal issues. Bands and artists in this genre usually look for fame and money.
R'nB genre was formed in the 50's by black artists who were taking apart from commercial tracks. They based their music in a kind of popular root coming from gospel and spirituals.
Electronic genre appeared in the last years of the 70's and grew stronger through the 80's. This music is based in computer sounds.