Definition of rill in US English:



  • 1A small stream.

    • ‘The river is about 30 m wide here, alternating between pools and rocky-bottomed shallow rills.’
    • ‘Slowing as Sara's viewpoint neared the surface, more and more details became clearer - craters large and small, passing rills and distant mountains, boulders everywhere.’
    • ‘Michael suggested the water should be channelled under the house to supply Robin's pond and a short rill in the back before being pumped to the front, where it supplies a fountain.’
    • ‘After a spell of rain, small rills are filled up with garbage.’
    • ‘The rill was a parched ravine now, as though some convulsion of the earth had bled the region dry of its lifeblood.’
    • ‘A linked watercourse is planned, with cascades, ponds and rills.’
    brook, rivulet, runnel, streamlet, freshet
    View synonyms
    1. 1.1 A shallow channel cut in the ground by running water.
      • ‘The characteristic forms of water erosion are rills and gullies.’
      • ‘But it is not quite a cascade, either, since the narrowness of the granite channel gives it something of the character of a formal rill.’
      • ‘As rills cut deeper and coalesce, gully erosion develops.’
      • ‘Flow velocity increases, and the increased energy detaches more soil particles and transports them in tiny channels called rills.’
      • ‘No evidence was observed of increased gully formation except in localized spots, nor was there any visible evidence of excessive rill or sheet erosion.’
      • ‘These rills generally develop in the same places each year.’
      • ‘These streams appear from the crevices of the rocks running through rills and gullies.’
    2. 1.2
      variant spelling of rille


[no object]
  • 1(of water) flow in or as in a rill.

    ‘the springwater rilled over our cold hands’
    1. 1.1as adjective rilled Indented with small grooves.
      ‘blocks of butter pounded into artful shapes with rilled paddles’


Mid 16th century: probably of Low German origin.