trillion

noun

tril·​lion ˈtri(l)-yən 

1

: a number equal to 1,000 times one billion see Table of Numbers

2

: an indeterminately large number

a trillion mosquitoes out tonight

trillion adjective

trillionth

ˈtri(l)-yən(t)th 

adjective or noun

Examples of trillion in a Sentence

Recent Examples on the Web

Nutrition experts say that resistant starch is one of the best things for your gut microbiome, the community of trillions of microbes that live in your intestine. —Anahad O’Connor, Washington Post, 3 Feb. 2026

Containing trillions of solar masses, such evolved, early protoclusters must be cosmically rare. —Big Think, 2 Feb. 2026

The timing of OpenAI’s IPO also comes as some investors are beginning to question whether generative AI can deliver returns that justify the trillions being poured into the sector. —Beatrice Nolan, Fortune, 30 Jan. 2026

Unlike language models trained on trillions of words scraped from the Internet, robotic manipulation data requires physical demonstrations that are expensive and time-consuming to collect. —Janakiram Msv, Forbes.com, 30 Jan. 2026

Word History

Etymology

French, from tri- + -illion (as in million)

First Known Use

1745, in the meaning defined at sense 2

Rhymes for trillion

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

Kids Definition

trillion

noun

tril·​lion ˈtril-yən 

1

: a number equal to 1,000 times one billion see number

2

: a very large number

a trillion mosquitoes out tonight

trillion adjective

trillionth

-yən(t)th 

adjective

trillionth noun