pi

word

/ˈpaɪ/
py
/pˈaɪ/
py

Definition

Pi is a mathematical constant, the ratio of a circle’s circumference to its diameter, approximately equal to 3.14159. It is often symbolized as π and used in geometry and calculations involving circles.

Usage & Nuances

'Pi' is a technical term used mainly in math and science. Always written as the Greek letter π in formulas. Not related to 'pie' (the dessert), which is a frequent learner mistake. Common phrases include 'pi day' (March 14).

Example Sentences

The symbol for pi is π.

basic

Even supercomputers keep trying to find more digits of pi.

natural

The value of pi is about 3.14.

basic

We use pi to find the area of a circle.

basic

On Pi Day, math lovers celebrate pi with fun activities.

natural

You can’t calculate the circumference of a circle without pi.

natural