English Reference
noun

meridian

n.
US /mɝˈɪdiən/ UK /mɛɹˈɪdiən/ merid·i·an UK spelling meridians

  1. 01 B2 Upper Intermediate Technical Science

    an imaginary line on the Earth's surface that goes from the North Pole to the South Pole.

    a great circle on the Earth's surface passing through the geographic poles, used to measure longitude.

    Simple

    The Prime Meridian passes through Greenwich in London and marks zero degrees longitude.

    In context

    Navigators calculate their east-west position by measuring the time difference between their local noon and the time at the prime meridian.

    Usage

    Often used with 'prime' to refer to the 0° longitude line.

    longitudegreat circle
  2. 02 C1 Advanced Literary

    the time when something is at its most successful or powerful point.

    the point of highest development or perfection; a figurative peak or zenith.

    Simple

    The empire reached its meridian during the eighteenth century before slowly losing power.

    In context

    Historians often debate whether the poet was at the meridian of his creative powers when he wrote his final epic.

    Teacher's tip

    This sense is literary; in modern everyday speech, 'peak' or 'height' is much more common.

  3. 03 C1 Advanced Technical Medicine

    any of the paths in the body that energy is said to flow through in traditional Chinese medicine.

    in traditional Chinese medicine, any of the pathways through which 'qi' or life force flows.

    Simple

    Acupuncture involves placing needles at specific points along a meridian to improve health.

    In context

    The practitioner explained that the treatment was designed to clear blockages in the lung meridian and restore balance to the body.

  4. 04 C2 Proficiency Technical Astronomy

    an imaginary circle in the sky that passes through the poles and the point directly above you.

    a great circle passing through the celestial poles and the zenith of a particular location.

    Simple

    The star will be at its highest point when it crosses the local meridian tonight.

    In context

    Astronomers wait for a celestial body to transit the meridian to take the most accurate measurements of its altitude.

    celestial circle
This entry
Level C1 · Advanced
Frequency Frequent
Updated