Technically it's "exchange".

To exchange BTC to USD is the same as selling an iPad for cash. In this case, you have multiple options. Peer-to-peer, official exchanges or the other dodgy websites up.

P2P means changing your BTC for cash in hand, gift cards, bank transfer (any method you can dream of) with other people (hence p2p) on a website such as paxful or localbitcoins. It's easy to get scammed so watch out for that. Changing on an official exchange such as bittrex could also be a possible option for you but it's considered harder in some cases (if you don't have ID on hand, time and a bit of patience) as it's very hard to exchange on these sites as a new member.