Leeward means the side or direction that is sheltered from the wind. If you stand behind a building on a windy day, you're on the leeward side, protected from the gusts that are hitting the other side. The opposite is windward, which faces directly into the wind.

Sailors use this word constantly because understanding wind direction can mean the difference between smooth sailing and dangerous conditions. When a ship sails on the leeward side of an island, the island blocks the wind, creating calmer waters. The leeward side of a mountain receives less rain because clouds drop most of their moisture on the windward side as they're pushed up and over.

You'll often see it in place names: the Leeward Islands in the Caribbean got their name because they're downwind of the Windward Islands. If you're camping and want to build a fire, you'd want to sit on the leeward side so smoke doesn't blow in your face.