sieve of Eratosthenes

noun phrase

sieve of Er·​a·​tos·​the·​nes -ˌer-ə-ˈtäs-thə-ˌnēz 

: a procedure for finding prime numbers that involves writing down the odd numbers from 2 up in succession and crossing out every third number after 3, every fifth after 5 including those already crossed out, every seventh after 7, and so on with the numbers that are never crossed out being prime

Word History

First Known Use

1803, in the meaning defined above