The story
From its rough resemblance to the English foot.
Etymology from Wiktionary, CC BY-SA 4.0.
Today it means: A chi, a traditional Chinese unit of distance based on the human forearm, now standardized variously as (Mainland China) ¹/₃ or (Taiwan) ¹⁰/₃₃ of a meter. Full definition →
From its rough resemblance to the English foot.
Etymology from Wiktionary, CC BY-SA 4.0.