Definition of phi
: the 21st letter of the Greek alphabet — see Alphabet Table
Keep scrolling for more
Test Your Vocabulary
February 2021 Words of the Day Quiz
-
- Which is a synonym of perdure?

Test your visual vocabulary with our 10-question challenge!
TAKE THE QUIZ
Spell words. Make bears.
TAKE THE QUIZLove words? Need even more definitions?
Merriam-Webster unabridged
Words at Play
Ask the Editors
Share phi
Time Traveler for phi
The first known use of phi was in the 15th century
See more words from the same century