Illinois
1 Americannoun
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a member of a confederacy of North American Indians of Algonquian stock, formerly occupying Illinois and adjoining regions westward.
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the Algonquian language of the Illinois and Miami Indians.
noun
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a state in the central United States: a part of the Midwest. 56,400 sq. mi. (146,075 sq. km). Springfield. IL (for use with zip code), Ill.
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a river flowing southwest from northeastern Illinois to the Mississippi River: connected by a canal with Lake Michigan. 273 miles (440 km) long.
noun
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Abbreviation: Ill.. IL. a state of the N central US, in the Midwest: consists of level prairie crossed by the Illinois and Kaskaskia Rivers; mainly agricultural. Capital: Springfield. Pop: 12 653 544 (2003 est). Area: 144 858 sq km (55 930 sq miles)
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a river in Illinois, flowing SW to the Mississippi. Length: 439 km (273 miles)
Pronunciation
The pronunciation of Illinois with a final , which occurs chiefly among less educated speakers, is least common in Illinois itself, increasing in frequency as distance from the state increases.
Discover More
Known as the “Land of Lincoln” because Abraham Lincoln began his political career there.
Other Word Forms
Etymology
Origin of Illinois
1715–25, < French, earlier Eriniouai, Ilinoués, etc., from an unidentified Algonquian language, apparently literally, “one who sounds normal” (i.e., “a person who speaks an Algonquian language”), equivalent to the (unattested) Proto-Algonquian elements elen- “ordinary” + -we “make sound”
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
High electricity rates, expensive land and regulatory hurdles mean that fewer, and smaller, facilities are currently planned than in Virginia, Texas, Georgia, Illinois or Arizona.
From Los Angeles Times • Jun. 2, 2026
There was the time, just a few years later, when I re-loaded that same car to move from Illinois back to California, with a whole new girlfriend as my passenger.
From Salon • Jun. 1, 2026
The Illinois team developed a process that preserves the advantages of single-crystal silicon while staying well below the thermal limit.
From Science Daily • May 30, 2026
The new investigation is being led by the US Attorney's Office for the Northern District of Illinois, one source told CBS.
From BBC • May 28, 2026
Scoville, who practiced law in Illinois, wasn't a criminal attorney.
From "Ambushed!" by Gail Jarrow
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Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.