Originally depicted farmland. The meaning later shifted to "circumference" and "cycle". Later the 口 component was added when 周 was used to refer to a geographical region to indicate that the character was only "mouthed", i.e. used for its sound. In simplified Chinese 周 is also used to mean "week", while in traditional Chinese this meaning is written with a separate character 週.

Evolution

Oracle script

(~1250-1000 BC)

Bronze script

Early Western Zhou (~1000 BC)

Seal script

Shuowen (~100 AD)

Clerical script

Eastern Han dynasty (25-220 AD)

Regular script

Modern

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