✨📕 The NEW Collegiate Dictionary, 12th Edition Over 5,000 words added — Learn More!
✨📕 The NEW Collegiate Dictionary — Learn More!

“growth substance”

We have one entry that includes the term growth substance.

plant growth substance

noun

: a growth regulator for plants

See the full definition

Word of the Day

Listen to the pronunciation of brackish

See Definitions and Examples »

Test Your Vocabulary

Challenging Standardized Test Words

  • high school student holding a pencil leaning over a sat test
  • Despite the cacophony, the student tried to study.
True or False

Test your knowledge - and maybe learn something along the way.

TAKE THE QUIZ
Play Blossom: Solve today's spelling word game by finding as many words as you can using just 7 letters. Longer words score more points.

Pick the best words!

PLAY
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

Games & Quizzes

See All
Play Quordle: Guess all four words in a limited number of tries. Each of your guesses must be a real 5-letter word.
Quordle Can you solve 4 words at once?
Play Blossom: Solve today's spelling word game by finding as many words as you can using just 7 letters. Longer words score more points.
Blossom Pick the best words!
Play Missing Letter: a crossword with a twist. Each of the 25 puzzle words start with a different letter of the alphabet. Which letter is missing?
The Missing Letter A daily crossword with a twist
cow coming home
Farm Idioms Quiz If you've got a pig in a poke - what exactly is a...
See All