Definition of loess in US English:



  • A loosely compacted yellowish-gray deposit of windblown sediment of which extensive deposits occur, e.g., in eastern China and the American Midwest.

    • ‘Companion studies of dust samples from the Sahara and the Saudi coast and loess from China show that the higher the calcium in the mineral, the more reactive they are in with nitric acid.’
    • ‘Many researchers have concluded this sediment is actually loess, or wind-blown silt, which is mixed with some clay and sand.’
    • ‘The thickest loess occurs in central China on the Loess Plateau, where it reaches a thickness of about 330 m near Lanzhou.’
    • ‘No one told us how they were shaped as silt deposits, called loess, that blew in from the Missouri River floodplain, beginning about 30,000 years ago.’
    • ‘Large areas of southern Arkansas are also covered by Pleistocene-era loess, with some deposits over 4 m thick.’


Mid 19th century: from German Löss, from Swiss German lösch ‘loose’.