Other forms: berths; berthed; berthing
A berth is a bed, usually stacked like bunk beds, on a train or a ship. If you're on an overnight train, you may want to spring for a berth instead of sitting up all night.
You may have heard the phrase "to give someone a wide berth" — that means to give them plenty of space. But if you want to use berth as a verb, you better be talking about parking a boat: to berth means to moor or dock a ship. The parking spot itself also happens to be called a berth. So if there's a big storm brewing, you best be sure to berth your boat securely in its berth.