西 is one of the four cardinal directions, where the sun sets.
Related words
Compounds
Usage
With locations, use の or に: 駅の西に (west of the station). For movement: 西へ行く (go west).
Pronunciation
In compounds 西 is often read せい or さい: 西洋 (the West), 関西 (the Kansai region), 東西 (east and west).