Meaning & use
pi
The mathematical constant, approximately 3.14159, equal to the ratio of a circle's circumference to its diameter.
See it in a sentence
Students memorized the first ten digits of pi for the school math competition.
The formula for the area of a circle multiplies pi by the radius squared.
A note on using this word
Represented by the Greek letter π; it is an irrational number, so its decimal digits never repeat or end.
Words with a similar meaning
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