Seasick means feeling nauseous and dizzy because of a boat's motion on the water. When you're seasick, your stomach feels queasy, you might get a headache, and the rocking of the waves makes you want to lie down or, in bad cases, throw up.

Seasickness happens because your inner ear, which helps you balance, sends signals to your brain that you're moving, but your eyes might tell your brain you're standing still. This confusion makes your body feel awful. Some people get seasick on small boats in choppy water, while others can handle rough seas without any problem. Similar feelings can happen in cars (carsick) or airplanes (airsick).

Sailors have developed tricks to fight seasickness over centuries of ocean travel: looking at the horizon, staying up on deck in fresh air, eating light foods like crackers, or focusing on a distant point. Some people take medicine before a boat trip to prevent it. The good news is that many people who get seasick at first gradually adjust to the motion after a day or two at sea, a process sailors call “getting your sea legs.”