what letter is pi

Pi is a letter from the Greek alphabet: uppercase Π and lowercase π.

Quick Scoop

• In the Greek alphabet, pi (π) is the sixteenth letter and corresponds to the sound “p,” like the English letter P.

• The math constant π (about 3.14159) uses this same lowercase Greek letter as its symbol.

• In English, we usually pronounce the letter and the constant as “pie.”

A tiny story to remember it

You can think of it this way:

The Greeks had a letter π that sounded like our P, and centuries later mathematicians borrowed that same letter to stand for the circle constant we now call “pi.”

So when you ask “what letter is pi,” the answer is: it’s the Greek letter π (pi), which plays the role that P does in the English alphabet.

TL;DR: Pi is the Greek letter π (uppercase Π), corresponding to the English letter P and used in math for the circle constant.

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