-ˌerəˈtästhəˌnēz
Usage: usually capitalized E
Etymology: after Eratosthenes fl 3d century B.C. Greek astronomer and geographer
: a device for finding prime numbers consisting of the writing down of the odd numbers from 3 up in succession and of erasing every third number after 3, every fifth after 5, every seventh after 7, and so on, the numbers remaining being prime