noun

• (philosophy, mysticism) A life force in traditional Chinese philosophy, culture, medicine, etc, related (but not limited) to breath and circulation.
  "Early Taoist philosophers and alchemists regarded ch'i as a vital force inhering in the breath and bodily fluids and developed techniques to alter and control the movement of ch'i within the body; their aim was to achieve physical longevity and spiritual power."

noun

• (Mainland China) The Chinese unit of length standardized in 1984 as ¹/₃ of a meter.
• (Taiwan) The Taiwanese unit of length standardized as ¹⁰/₃₃ of a meter, identical to the Japanese shaku.
• (Hong Kong) The chek or Hong Kong foot, a unit of length standardized as 0.371475 meters.

name

• (historical, dated) Qi, an ancient Chinese duchy, and later kingdom, under the Zhou dynasty

noun

• (informal) Clipping of Chihuahua.