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

photosystem

play
noun pho·to·sys·tem \ˈfō-tō-ˌsis-təm\

Definition of photosystem

  1. :  either of two photochemical reaction centers consisting chiefly of photosynthetic pigments complexed with protein and occurring in chloroplasts: a :  one that absorbs light with a wavelength of about 700 nanometers —called also photosystem I b :  one that absorbs light with a wavelength of about 680 nanometers —called also photosystem II



1964

First Known Use of photosystem

1964


Seen and Heard

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

WORD OF THE DAY

February 10, 2016

to put in good humor

Get Word of the Day daily email!

WORD GAMES

Take a 3-minute break and test your skills!

image1037863653

Which of the following refers to thin, bending ice, or to the act of running over such ice?

spindrift duvet kittly-benders pince-nez
Name That Thing

10 quick questions: hear them, spell them, and see how your skills compare to the crowd.

TAKE THE QUIZ
SCRABBLE® Sprint

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

TAKE THE QUIZ