Meaning & use
pi
Last updated
Meanings
noununcountablemathematics
The number, about 3.14159, found by dividing the distance around any circle by the distance across it.
Grammar: Uncountable and written without an article: the value of pi.
Patterns
- the value of pi
Students memorize digits of pi for fun.
Multiply the diameter by pi to find the circumference.
Pi never ends and never repeats.
nouncountable
The sixteenth letter of the Greek alphabet, written π.
Grammar: Countable: Greek letters such as pi and sigma.
The symbol for pi is a Greek letter.
Fraternities often use pi in their names.
He wrote a pi on the board.
Word forms
| plural | pis |
|---|
Common combinations
- value of pi
- Archimedes estimated the value of pi.
- digits of pi
- She can recite a hundred digits of pi.
- pi day
- Pi Day is celebrated on March 14.
- calculate pi
- Computers can calculate pi to trillions of places.
- multiply by pi
- Multiply the radius squared by pi.
Synonyms and how they differ
- π
- The symbol π is how pi is written in formulas, whereas the word pi is used in speech and text.
- 3.14
- 3.14 is a rounded approximation, but pi itself has endless digits.
- circle constant
- Circle constant is a descriptive term, but pi is the standard name.
Word family
- pi day noun
- March 14, celebrated as a math holiday
- pie noun
- a baked dish; sounds the same as pi but is unrelated
- irrational adjective
- describing numbers like pi that cannot be written as fractions
Commonly confused: pi or pie?
pi vs pie
Pie is a food that sounds the same but is spelled differently, while pi is the math constant.
Practice
To find the circumference of a circle, multiply its diameter by ___.
Choose one answer.
Pi is the constant used for circles. Pie and pea are sound-alike words with different meanings, and phi is another Greek letter.
Make it your own
Write a sentence using “pi”, then check it and compare it with the examples above.