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

The light from the Pinwheel traveled for 25 million years across the universe – about 150 quintillion miles – to get to my telescope. —Jarred Roberts, The Conversation, 20 May 2025

One prominent example is Hewlett Packard Enterprise’s (HPE) Frontier supercomputer, which can perform a quintillion (1,000,000,000,000,000,000) calculations per second – over a million times more than the number of stars in the Milky Way galaxy. —Cat Wang, Forbes.com, 19 May 2025

The odds of getting a perfect March Madness bracket are astronomically low, estimated at around 1 in 9.2 quintillion. —Jay Ginsbach, Forbes, 3 Mar. 2025

Complete randomness would be a 9.2 quintillion chance of picking the perfect NCAA bracket. —Ars Technica, 20 Mar. 2025

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