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

Medical Dictionary

photochromogen

play
noun pho·to·chro·mo·gen \ˌfōt-ō-ˈkrō-mə-jən\

Medical Definition of photochromogen

  1. :  a microorganism especially of the genus Mycobacterium (as M. kansasii) that has little or no pigment when grown in the dark but becomes highly pigmented when grown in light




Seen and Heard

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

WORD OF THE DAY

the Celtic May Day festival

Get Word of the Day daily email!

WORD GAMES

Take a 3-minute break and test your skills!

image567572573

Which of these is a synonym of unctuous?

angry maudlin prompt oily
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