Definition of phototropism
: a tropism in which light is the orienting stimulus
Test Your Vocabulary
Great Words for Scrabble
-
- Which of the following Q-without-U words means the number five in cards or dice?

Can you spell these 10 commonly misspelled words?
TAKE THE QUIZ
A daily challenge for crossword fanatics.
TAKE THE QUIZLove words? Need even more definitions?
Merriam-Webster unabridged
Share phototropism
Time Traveler for phototropism
The first known use of phototropism was in 1899
See more words from the same year