[ gram-neg-uh-tiv ]

adjective(often lowercase)
  1. (of bacteria) not retaining the violet dye when stained by Gram's method.

Origin of Gram-negative

First recorded in 1905–10; see origin at Gram's method

Words Nearby Gram-negative Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024

How to use Gram-negative in a sentence

British Dictionary definitions for Gram-negative


  1. designating bacteria that fail to retain the violet stain in Gram's method

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

Scientific definitions for gram-negative


  1. Relating to a group of bacteria that do not change color when subjected to the laboratory staining method known as Gram's method or Gram's stain. Gram-negative bacteria have relatively thin cell walls and are generally resistant to the effects of antibiotics or the actions of the body's immune cells. Gram-negative bacteria include E. coli and the bacteria that cause gonorrhea, typhoid fever, rickettsial fever, cholera, syphilis, plague, and Lyme disease. Compare gram-positive.

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