周
zhōu
week
weekly; variant of 周[zhou1]
enclosure (冂) + earth (土) + mouth (口) = a complete cycle
周 originally depicted land divided and enclosed on all sides — a complete, bounded territory. The sense of 'all around' and 'full circuit' gave rise to the modern meaning of a week: one full turn of days.
冂EnclosureSemantic
口MouthSemantic
土EarthSemantic