What is the name of the item used to make music from your iPhone 5 play in the car?

What is the name of the item used to make music from your iPhone 5 play in the car?

You could use a couple things (although a stock/factory head unit might not have AUX or USB input if it is older):

AUX (Auxiliary) cord: It fits in the 3.5mm headphone jack. Connects to another 3.5mm jack on the headunit.

USB Cord: Uses the iPod connection, and the other end is USB to hook up to the headunit

FM Transmitter: Fits in the 3.5mm headphone jack, transmits the music over a radio signal and you tune your head unit into that particular radio frequency. (be aware that there can be static and interference that will lessen your sound quality)

Cassette Tape Adapter: If your stock head unit has a Cadette deck, then this cassette fits in, and has a 3.5mm connection coming out of it that will go into your iPhone's headphone jack. It will convert the signal into a form usable by the cassette deck. (this way will also probably get you some static and lessen your sound quality, but this is still far better than an FM transmitter)