Definition of Illinoian in English:



  • 1Relating to or denoting a Pleistocene glaciation in North America, preceding the Wisconsin and approximating to the Saale of northern Europe.

    • ‘The forest studied in Pike County, Illinois was on Illinoian glacial till in the Glaciated Section of the Mississippi River Border Division.’
    • ‘The Labradorean domain was more extensive in Minnesota and Illinois during the Illinoian glaciation than in the Wisconsinan glaciation.’
    • ‘During glacial retreat in the second of three advances, the flat Illinoian till plain was lain down in the lower third of the state north of Shawnee Hills.’
    • ‘These well-drained, sloping soils developed on Illinoian glacial till overlain with loess and have a compact fragipan that restricts root growth.’
    • ‘This preserve is located on a käme (a hill or mound of stratified drift deposited by glacial meltwater) formed during the Illinoian glacial epoch.’
    1. 1.1as noun the Illinoian The Illinoian glaciation or the system of deposits laid down during it.


Mid 19th century: from Illinois + -an.