Pi2

Pi2 is a term with multiple uses. Most commonly, it denotes the mathematical quantity π^2, the square of the constant π. The symbol π represents the ratio of a circle's circumference to its diameter, approximately 3.14159. Squaring π yields π^2 ≈ 9.8696044. π^2 is irrational, and because π is transcendental, π^2 is also transcendental. In mathematics, π^2 appears in various formulas and integrals; it is the value that arises in the Basel problem, where the sum of reciprocals of squares equals π^2/6.

In other contexts, "Pi 2" or "pi2" can refer to hardware, most notably the Raspberry Pi 2 Model B, a 2015 single-board computer released by the Raspberry Pi Foundation. In informal usage, some people shorten the name to "Pi 2." The Raspberry Pi 2 Model B is part of the Raspberry Pi family and is used widely in education, hobbyist projects, and entry-level computing tasks. The term may also appear in branding or product names in other domains, but those uses are less common.

Overall, pi2 most often appears in mathematical discussions as a shorthand for π^2, while in technology contexts it is sometimes used informally to denote the Raspberry Pi 2 Model B.