A term used particularly by promiscuous girls today, which has supplanted the term "dating". Previously, women would go on dates with men where they would get to know the man, and then be returned to their home safely. Now, women "hang out" which means they go to bars or friends houses, drink, pass out and wonder why their genitals hurt the next morning.
"So, like, me and my BFF Sarah were hanging out with some dude she met off Myspace and we got SO trashed and started dancing on the bar and making out."
"so... uh... what does your dad think about this?"
"Dad?!? Like whatever I don't have a dad! I'm thinking about getting a new tattoo!"