Westerly means toward the west, or coming from the west. When you travel in a westerly direction, you're heading west. When weather forecasters talk about westerly winds, they mean winds blowing from the west toward the east.

The word works as both an adjective and an adverb. A ship sailing a westerly course is moving west. Birds migrating westerly are flying toward the west. Weather systems often move in a westerly direction across North America, which is why meteorologists watch storms approaching from the western states.

Westerly is more formal and precise than simply saying “west.” A hiker might say “we walked west,” but a ship's captain recording the voyage in a log would write “we sailed westerly.” Scientists, navigators, and weather experts use westerly when they need to be exact about direction.

The word can sometimes be confusing because westerly winds blow from the west, not toward it. Think of it as the wind's home direction: a westerly wind comes from its home in the west and travels east. This naming pattern applies to all wind directions: northerly, southerly, easterly, and westerly.