西 was originally a picture of a bird's nest. At sunset, birds return to roost — and the sun sets in the WEST. So the nest came to stand for the western direction. (You can imagine the nest shape in the character.)
西 is west, the second half of 东西 (thing/stuff). It also names the West in the cultural sense: 西方 (the West/Occident), 西餐 (Western food), 西药 (Western medicine, vs 中药 Chinese medicine). 西安 (Xi'an) — 'Western Peace' — was the ancient capital and the start of the Silk Road. East and west, 东 and 西, frame the Chinese map of the world.
A bird's nest where birds roost at sunset — the WEST.
西 marks 'Western' things: 西方 (the West), 西餐 (Western food), 西医 (Western medicine). Its partner 东 gives 东方 (the East). The two directions split the whole world.