Encyclopedia > Pi (letter)

Article Content

Pi (letter)

Pi (Π π) is the 16th letter of the Greek alphabet and has a numeric value of 80.

The upper-case letter Π is used as a symbol for:

In mathematics, the product operation.
In textual criticism, Codex Petropolitanus, a 9th century, uncial codex of the Gospels, now located in St. Petersburg, Russia.

The lower-case letter π is used as a symbol for:

In economics, profit.
In mathematics, the constant pi, which is the ratio of the circumference to the diameter of a circle.
In number theory, the function π(x) is the number of primes that are less than or equal to x.
In particle physics, π⁰, π⁺ and π^- are three forms of pi meson.

Featured Article

Johann Karl Friedrich Rosenkranz

... the "centre," midway between Erdmann and Gabler on the one hand, and the "extreme left" represented by Strauss, Feuerbach and Bruno Bauer. Of his numerous writings, ...