Meaning & Definition of word "Pi"

Pi

/paɪ/

noun:

  • 1. The ratio of the circumference of a circle to its diameter, approximately equal to 3.14159.
    • Example: In mathematics, pi is often represented by the Greek letter π.
  • 2. A mathematical constant used in various formulas, especially those involving circular or periodic properties.
    • Example: The formula for the area of a circle is A = πr², where r is the radius.
  • 3. A symbol (π) used in mathematics to represent the aforementioned constant.
    • Example: When calculating the circumference, the formula uses the symbol π to denote pi.

verb:

  • 1. To use the value of pi in calculations.
    • Example: In the geometry class, we learned how to pi the dimensions of the circle to find its area.

Etymology

From the Greek letter π (pi), which stands for the word 'periphery' and was first used in this mathematical sense by the Welsh mathematician William Jones in 1706.

Common Phrases and Expressions

Pi Day:

March 14, celebrated in honor of the mathematical constant pi.

Cutting corners:

To do something in a cheaper or easier way, sometimes related to estimating using pi.

On the pi:

Referring to something done in a precise or careful manner, often in mathematics.

Related Words

circle:

A round plane figure whose boundary consists of points equidistant from a fixed point (the center).

radius:

A straight line from the center to the circumference of a circle or sphere.

circumference:

The enclosing boundary of a curved geometric figure, especially a circle.

Slang Meanings of pi

Meaning: A mathematical reference for accuracy or perfection.

Example Sentence: He wants his calculations to be as precise as pi.

Meaning: To 'pi' someone off signifies to annoy or irritate them.

Example Sentence: Stop talking about pi; you're really pi-ing me off!