quintillion

noun

quin·​til·​lion kwin-ˈtil-yən 

US : a number equal to 1 followed by 18 zeros see Table of Numbers

also, British : a number equal to 1 followed by 30 zeros see Table of Numbers

quintillion adjective

quintillionth

kwin-ˈtil-yən(t)th 

adjective or noun

Examples of quintillion in a Sentence

Recent Examples on the Web

New simulations Frontier, the third fastest exascale supercomputer in the world, after the Aurora and El Capitan, is capable of performing more than two quintillion calculations per second. —Georgina Jedikovska, Interesting Engineering, 21 Apr. 2026

In 1946, Hungary replaced the pengö with a new currency—the forint—at a rate of 400 quintillion pengö to 1 forint, which eventually stabilized the economy. —Encyclopedia Britannica, 14 Apr. 2026

Both of these decay rapidly into even more particles, so in the end, ultrahigh-energy protons (with more than 50 quintillion eV) from distant galaxies should never reach us. —Phil Plait, Scientific American, 3 Apr. 2026

The late DePaul mathematics professor Jeffrey Bergen calculated the odds at 1 in 9.2 quintillion, assuming every game is a 50-50 proposition, or about 46 million times the number of stars in our galaxy. —Dave Skretta, Chicago Tribune, 26 Mar. 2026

Word History

Etymology

Latin quintus + English -illion (as in million)

First Known Use

circa 1690, in the meaning defined above

Rhymes for quintillion

• castilian
• civilian
• cotillion
• pavilion
• postilion
• quadrillion
• reptilian
• vermilion
• vermillion
• billion
• million
• pillion

Kids Definition

quintillion

noun

quin·​til·​lion kwin-ˈtil-yən 

US : a number equal to 1 followed by 18 zeros see number

also, British : a number equal to 1 followed by 30 zeros see number