pi

/paɪ/
noun
  1. The 16th letter of the Greek alphabet (Π, π).
    • In fraternity names, pi is a common letter.
    • He wrote the symbol for pi on the chalkboard.
    • The Greek letter pi is often used in mathematics.
  2. The mathematical constant (approximately 3.14159) representing the ratio of a circle's circumference to its diameter.
    • Students celebrate Pi Day on March 14th because the date matches 3.14.
    • To find the area of a circle, multiply pi by the radius squared.
    • Pi is an irrational number, meaning its decimal never ends.
What does "pi" mean? | whatsthatwordmean | whatsthatwordmean