404
Americannoun
-
Also called 404 error. Computers. an error message sent by a web server to a browser when the user has typed an incorrect URL, tried to access a web page that is no longer available, or clicked on a broken link on a web page.
They must have taken down their website;
I keep getting that annoying “404 - File Not Found” message.
-
Slang. a person who is stupid or uninformed.
noun
Etymology
Origin of 404
First recorded in 1995–2000
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.
I looked over at 404 reporter Rebecca Castillo in envy, knowing she was about to witness the Brooklyn outfit for the first time.
From Los Angeles Times ● Aug. 24, 2026
The symbol for that facility, 404 Media reported, was a sharp-toothed green dinosaur holding an open book.
From The Wall Street Journal ● Aug. 22, 2026
There are still transparency laws that apply to Flock databases, which is how 404 Media and other media outlets have discovered abuses of the technology.
From Salon ● Aug. 14, 2026
The Dow Jones Industrial Average fell 404 points, or 0.8%, while the S&P 500 was off 0.9%.
From Barron's ● Mar. 7, 2026
Mari did, but a 404 error popped up.
From "Boy 2.0" by Tracey Baptiste
![]()
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.