ENGLISH
REFERENCE

chi

n.
US //ˈkaɪ// UK //tʃˈaɪ// chi
  1. 1 life force (n.)
    B2 Upper Intermediate Religion

    the energy or life force that people in traditional Chinese medicine and philosophy believe flows through the body.

    the vital life force or energy whose flow is central to traditional Chinese medicine, martial arts, and philosophy.

    Example

    The teacher told us to focus on our chi while we practiced the slow movements of Tai Chi.

    Example

    Practitioners of traditional Chinese medicine believe that an imbalance or blockage of chi within the body's meridians can lead to physical illness.

    Usage

    Often spelled 'qi' in modern English contexts.

    Teacher's tip

    Explain to students that 'qi' is the more common academic spelling, while 'chi' is frequently seen in older texts or popular culture.
  2. 2 Greek letter (n.)
    C1 Advanced Technical

    the twenty-second letter of the Greek alphabet, written as X.

    the twenty-second letter of the Greek alphabet, represented by the symbol Χ.

    Example

    The professor used the Greek letter chi to represent a specific value in the equation.

    Example

    In statistics, the chi-squared test is a common method used to determine if there is a significant difference between expected and observed frequencies.

    Usage

    Usually appears in mathematical, scientific, or linguistic contexts.

  3. 3 Chicago (n.)
    C1 Advanced American English Slang Informal

    a short, informal name for the city of Chicago.

    a colloquial clipping or nickname for the city of Chicago, Illinois.

    Example

    He grew up in Chi and still goes back every summer to visit his family.

    Example

    The rapper often references his upbringing in Chi-town, using the city's nickname to establish a sense of local authenticity in his lyrics.
  4. 4 Chinese unit of length (n.)
    C2 Proficiency Technical

    a traditional Chinese unit of length, similar to a foot.

    a traditional Chinese unit of linear measure, historically based on the length of a forearm and now standardized in various regions.

    Example

    The old carpenter measured the wood using the traditional chi instead of meters.

    Example

    While the metric system is official, some local markets still use the chi to measure fabric and traditional building materials.

    Usage

    The exact length varies between Mainland China, Taiwan, and Hong Kong.
    • chinese foot
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Last updated June 20, 2026