Definition of epilimnion in English:



  • The upper layer of water in a stratified lake.

    • ‘The chemistry of the two parts of a freshwater lake, the epilimnion and the hypolimnion, is affected by biological processes and by circulation.’
    • ‘The amount of bacterial cells imported via the inlets in relation to bacterioplankton cells produced in the epilimnion of the lakes was also determined.’
    • ‘At each pond, we took two replicate water samples from the epilimnion using an integrated depth sampler; we took samples from the surface to 1.25 m in Monday Bog and to 1.75 m in Wednesday Bog.’
    • ‘The sampling depth of 1.5 m was near the midpoint of the epilimnion depth in each lake.’
    • ‘Experiments were conducted in the epilimnion of a high-UV system at midday and in late afternoon.’


Early 20th century from epi-‘above’ + Greek limnion (diminutive of limnē ‘lake’).