adj, noun ·Rare ·Advanced level

Definitions

Noun

1. 1
   Alternative form of Illinoisan. alt-of, alternative
2. 2
   A stage of the last Ice Age in North America, lasting from around 190,000 to 130,000 years ago.

Adjective

1. 1
   Alternative form of Illinoisan. alt-of, alternative, not-comparable
2. 2
   Of or relating to the Illinoian stage. not-comparable

   "the Illinoian glaciation"

Etymology

From Illinois + -an.

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.