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

As gut health becomes a growing focus in the wellness world, experts point to the microbiome — the trillions of bacteria living in the digestive tract — as a key player in everything from digestion to immunity. —Deirdre Bardolf, FOXNews.com, 27 Apr. 2026

In a world filled with trillions upon trillions of atoms, spotting a handful that barely exist sounds almost impossible. —Rupendra Brahambhatt, Interesting Engineering, 25 Apr. 2026

This process is mainly thought to result from synaptic plasticity, or changes to the trillions of connections between neurons. —Yasemin Saplakoglu, Quanta Magazine, 24 Apr. 2026

With home equity levels in the country hitting a record high last year, however, and with trillions of dollars considered borrowable right now, withdrawing $50,000 worth of home equity should be relatively easy for current homeowners. —Matt Richardson, CBS News, 22 Apr. 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