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mainframe

American  
[meyn-freym] / ˈmeɪnˌfreɪm /

noun

Computers.

  1. a large computer, often the hub of a system serving many users.

mainframe British  
/ ˈmeɪnˌfreɪm /

noun

    1. a high-speed general-purpose computer, usually with a large storage capacity

    2. ( as modifier )

      mainframe systems

  2. the central processing unit of a computer

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
mainframe Scientific  
/ mān′frām′ /

  1. A large, often powerful computer, usually dedicated to lengthy, complex calculations or set up for use by many people simultaneously.

  2. Compare personal computer

mainframe Cultural  

  1. A large, powerful computer system. A mainframe computer typically carries out complex calculations and is shared by many users. (Compare personal computer.)

Etymology

Origin of mainframe

First recorded in 1960–65; main 1 + frame

Compare meaning

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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.

The analyst said investors might dispute his call, given concern that Anthropic’s Claude Code tool will disrupt IBM’s mainframe business.

From Barron's • Feb. 25, 2026

He views the mainframe business as “resilient” given examples from IBM of how customers are growing, not shrinking, their workloads.

From MarketWatch • Feb. 24, 2026

In his view, although alternatives have been available for decades, clients are sticking with mainframe for a host of reasons: reliability and speed advantages, better cost efficiency at scale, and security such as quantum-safe encryption.

From Barron's • Feb. 24, 2026

“IBM’s customers have had ample opportunities to migrate off of mainframe and are sticking with the platform given inherent advantages.”

From MarketWatch • Feb. 24, 2026

Despite Mother’s “get out of jail free” card, she was still determined to climb the wall and hack into the company’s mainframe.

From "City Spies" by James Ponti

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.