Mineh Ishida, has been a DJ for over 15 years. He's played all over the US and internationally

All of the answers here essentially talk about "disk jockeys" or DJs as people who play music. It's true that DJ's choose music. In the past they used vinyl records and thus the name. Over time that evolved to CD's and now digital music.

A DJ may be hired for a party or a radio station, and recently "celebrity" DJs who release their own mixes of music have become popular.

It's so much more than that though.

A DJ is someone who pays attention to an audience and chooses music that engages them. It's a craft that involves watching the crowd and reacting to them. Moving their emotions through the journey that the DJ chooses.

For example... a wedding DJ may have to know when to play slow romantic music, and then change it up to high tempo party music. He has to do this in a method that the crowd can accept.

An EDM (Electronic Dance Music) DJ, has to build the energy in the audience and know how to put the right texture and builds into the music to make a largely repetitive genre of music interesting and emotionally connectable.

Ultimately, a DJ is someone who connects people to music through song selection.