Definition of diel in English:



  • Denoting or involving a period of twenty-four hours.

    ‘tidal and diel cycles’
    • ‘Specimens were collected over a broad range of times to ensure that foods consumed throughout the diel cycle were represented.’
    • ‘The tagging data are providing new insights into the seasonal movements, diel thermal body temperature cycles, feeding energetics and habitat utilization of Pacific bluefin tuna.’
    • ‘Water movement and diel cycles of internal water distribution between water-storage hydrenchyma and photosynthetic chlorenchyma has also been demonstrated for A. deserti, Ferocactus acanthodes and Opuntia ficus-indica.’
    • ‘That correlation may also occur because gulls follow diel cycles of puffin activity attacking most often in the morning when puffin returns are likely to be highest.’
    • ‘Two additional cruises were conducted during calm periods to determine diel variation in the vertical distribution of C. concholepas competent larvae.’


1930s: from Latin dies day + -(a)l (see -al).