gram-negative

adjective

gram-neg·a·tive ˈgram-ˈne-gə-tiv

: not holding the purple dye when stained by Gram's stain

—used chiefly of bacteria

Example Sentences

Recent Examples on the Web Shigella bacteria are gram-negative bacteria, shaped like rods, recognized worldwide as the most common cause of dysentery, a gastrointestinal illness resulting in severe diarrhea. —

CBS News, 1 Mar. 2023

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'gram-negative.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1907, in the meaning defined above

Time Traveler

The first known use of gram-negative was in 1907

See more words from the same year

Cite this Entry

Style

“Gram-negative.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/gram-negative. Accessed 31 Mar. 2023.

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Medical Definition

gram-negative

adjective

gram-neg·a·tive ˈgram-ˈneg-ət-iv

: not holding the purple dye when stained by Gram's stain

—used chiefly of bacteria

Last Updated: 13 Mar 2023 - Updated example sentences

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