1) Illinoisan 
[stage] The Illinoian Stage is the name used by Quaternary geologists in North America to designate the period of geologic time of ~191,000—130,000 years ago, a period of ~{Mya|0.191-0.130|million years} during the middle Pleistocene when sediments comprising the Illinoian Glacial Lobe were deposited. It precedes the Sangamonian stage and...
Pertaining to the classical third glacial stage of the Pleistocene Epoch in North America, between the Yarmouthian and Sangamonian interglacial stages.
the third stage of the glaciation of North America during the Pleistocene. · Illinoisan.