west: the direction of the setting sun, and the western side or region it names
This is the plain Hebrew word for west, and it names the direction by the sunset. It is built on the same root as the word for "evening," so at heart it means the place where the sun goes in. Older Hebrew usually said west another way, by pointing at the Mediterranean lying out on that side and simply calling it the sea (יָם). This word belongs to the later books, and in them it has become the ordinary term.
About half of its uses are flat map work, most of them in Chronicles. It marks which side of the Jordan a family of officials served on, which gate a group of temple guards drew by lot, which side of the city of David a wall or a water channel ran along, and which town lay out west of another. In these places west is a bearing and nothing more.
The other half sits in poetry and prophecy, where west is set opposite east (מִזְרָח) to draw the widest line a person can imagine. Because the two words name the two ends of the sun's daily journey, putting them together is a way of saying "the whole world, edge to edge": God gathers his scattered people from both horizons, he carries sins off as far as the one is from the other, and his name is feared from one side of the sky to the other. The two uses are the same word at two scales, the near one and the farthest one there is.