Share this entry
Gram stain Syllabification: Gram stain

Definition of Gram stain in English:


A staining technique for the preliminary identification of bacteria, in which a violet dye is applied, followed by a decolorizing agent and then a red dye. The cell walls of certain bacteria (denoted Gram-positive) retain the first dye and appear violet, while those that lose it (denoted Gram-negative) appear red. Also called Gram’s method.
Example sentences
  • The use of standard biochemical testing rather than commercial systems has been recommended for identification of Gram-negative nonfermenting bacteria.
  • Endotoxin, the highly inflammatory surface component of Gram-negative bacteria, has been previously implicated in the morbidity and mortality of a number of clinical settings, including patients undergoing cardiac surgery.
  • Moreover, single findings can occasionally be very powerful and definitive, just as the results of certain formal diagnostic tests (such as a spinal fluid Gram stain showing bacteria).


Late 19th century: named after Hans C. J. Gram (1853–1938), the Danish physician who devised the method.

Definition of Gram stain in:
Share this entry

What do you find interesting about this word or phrase?

Comments that don't adhere to our Community Guidelines may be moderated or removed.

Subscribe to remove ads and access premium resources