nine n. in a percentage between 99 and 100, a place on either side of the decimal point given a value of nine and counted in serial to indicate a number very near 100 percent, such as in measurements of reliability, accuracy, purity, etc. Editorial Note: Common forms are five nines, meaning 99.999%, and six nines, meaning 99.9999%. Also used attributively: the company offers five-nines reliability guarantees. (source: Double-Tongued Dictionary)
Further reading
Enthusiastic book recommendations! Martha’s savoring the biography of Alexander von Humboldt, the 19th-century explorer, polymath, and naturalist who revolutionized our understanding of nature and predicted the effects of human activity on...
We use the term Milky Way for that glowing arc across the sky. But how people picture it varies from culture to culture. In Sweden, that starry band goes by a name that means “Winter Street,” and in Hawaii, a term for the Milky Way...