ENGLISH
REFERENCE

hormone

n. · v.
US //ˈhɔɹˌmoʊn// UK //hˈɔːməʊn// hor·mone
  1. 1 biological messenger (n.)
    B2 Upper Intermediate Science

    a natural chemical in your body that tells your organs how to work.

    a regulatory substance produced in an organism and transported in tissue fluids such as blood or sap to stimulate specific cells or tissues into action.

    Example

    Insulin is a hormone that helps your body control the amount of sugar in your blood.

    Example

    The endocrine system releases hormones directly into the bloodstream, where they travel to target receptors to regulate metabolic processes and maintain homeostasis.

    Usage

    Usually a countable noun when referring to specific types like insulin or adrenaline.
    • chemical messenger
  2. 2 synthetic medication (n.)
    B2 Upper Intermediate Medicine

    a man-made version of a natural hormone used as medicine.

    a synthetic compound or pharmaceutical product designed to mimic the physiological effects of a natural hormone.

    Example

    The doctor prescribed a hormone cream to help with her skin condition.

    Example

    Patients undergoing certain treatments may require synthetic hormones to compensate for glandular deficiencies or to suppress specific physiological responses.
    • synthetic hormone
  3. 3 plant growth substance (n.)
    C1 Advanced Technical Science

    a chemical in plants that helps them grow or flower.

    any of various organic compounds, such as auxin or gibberellin, that regulate plant growth and development.

    Example

    Farmers use a special hormone to make the fruit ripen at the same time.

    Example

    Plant hormones, or phytohormones, coordinate growth and responses to environmental stimuli by regulating gene expression and cell division.
    • phytohormone
  4. 4 to treat with chemicals (v.)
    C2 Proficiency Informal Technical

    to give hormones to an animal or plant to make it grow faster.

    to treat or inject an organism with hormones, often for agricultural or experimental purposes.

    Example

    Some people worry about eating meat from cows that have been hormoned.

    Example

    The livestock were hormoned to accelerate muscle development, a practice that remains controversial in several international markets.

    Usage

    This transitive verb use is relatively rare and often carries a negative connotation in consumer contexts.

Origin

Learned borrowing from Ancient Greek ὁρμῶν (hormôn), present participle of ὁρμάω (hormáō, “to set in motion, to urge on”), from ὁρμή (hormḗ, “rapid motion forwards, onrush, onset, assault, impulse to do a thing, effort”).

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

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Last updated June 20, 2026