phi

noun

ˈfī How to pronounce phi (audio)
: the 21st letter of the Greek alphabet see Alphabet Table

Word History

Etymology

Middle Greek, from Greek phei

First Known Use

15th century, in the meaning defined above

Time Traveler
The first known use of phi was in the 15th century

Phrases Containing phi

Dictionary Entries Near phi

phew

phi

phial

See More Nearby Entries 

Cite this Entry

“Phi.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/phi. Accessed 24 Apr. 2024.

Copy Citation

Share

Kids Definition

phi

noun
ˈfī How to pronounce phi (audio)
: the 21st letter of the Greek alphabet
—Φ or φ

More from Merriam-Webster on phi

Britannica.com: Encyclopedia article about phi

Love words? Need even more definitions?

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

Popular in Grammar & Usage

See All

Commonly Misspelled Words

How to Use Em Dashes (—), En Dashes (–) , and Hyphens (-)

Absent Letters That Are Heard Anyway

How to Use Accents and Diacritical Marks

On 'Biweekly' and 'Bimonthly'
See All

Popular in Wordplay

See All

The Words of the Week - Apr. 19

10 Words from Taylor Swift Songs (Merriam's Version)

9 Superb Owl Words

10 Words for Lesser-Known Games and Sports

Your Favorite Band is in the Dictionary
See All

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 Word Game You can make only 12 words. Pick the best ones!
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?
Missing Letter A crossword with a twist
winning words from the national spelling bee logo
Spelling Bee Quiz Can you outdo past winners of the National Spelli...