Quantcast
Merriam-Webster Logo
  • Dictionary
  • Thesaurus
  • Scrabble
  • Spanish Central
  • Learner's Dictionary

Gram's stain

play
noun \ˈgramz-\

Definition of Gram's stain

  1. 1 :  a method for the differential staining of bacteria by treatment with a watery solution of iodine and the iodide of potassium after staining with a triphenylmethane dye (as crystal violet) —called also Gram's method

  2. 2 :  the chemicals used in Gram's stain



Variants of gram's stain

or

Gram stain

play \ˈgram-\

Origin and Etymology of gram's stain

Hans C. J. Gram †1938 Danish physician


First Known Use: 1903


Medical Dictionary

Gram's stain

noun

Medical Definition of Gram's stain

  1. 1:  a method for the differential staining of bacteria that involves fixing the bacterial cells to a slide and staining usually with the basic dye crystal violet, treating with an iodine solution to fix the dye, washing with acetone or alcohol to decolorize the dye, and counterstaining usually with a red safranine dye which shows up only if the crystal violet has been decolorized, that results in gram-positive bacteria retaining the purple dye and gram-negative organisms having it decolorized so that the red counterstain shows up, and that is believed to depend on differences in the structure and composition of the bacterial cell walls which facilitate or prevent the decolorization of the crystal violet dye by the alcohol or acetone—called also Gram's method

  2. 2:  the chemicals used in Gram's stain



Variants of gram's stain

or

Gram stain

\ˈgram-\play

Seen and Heard

What made you want to look up Gram's stain? Please tell us where you read or heard it (including the quote, if possible).

WORD OF THE DAY

a very small amount

Get Word of the Day daily email!

WORD GAMES

Take a 3-minute break and test your skills!

alphabet-pasta-spelling-help

Which is the correct spelling?

acommadate accomodate accommodate acommodate
Name That Thing

Test your visual vocabulary with our 10-question challenge!

TAKE THE QUIZ
SCRABBLE® Sprint

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ