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

Here is what to know about the trillions of bacteria in your mouth and why researchers now treat them as a full-body health signal. — Allison Palmer, Sacbee.com, 2 July 2026

For stellar-mass black holes, however, the process would take around 10⁶⁷ years—trillions upon trillions of times longer than the current age of the universe. — Kaif Shaikh, Interesting Engineering, 29 June 2026

Trading the doomsday script for innovation, adaptation and development would save trillions of dollars — and do far more for both people and the planet. — Bjorn Lomborg, The Orlando Sentinel, 26 June 2026

Fibre can also be a prebiotic, feeding the trillions of gastrointestinal bacteria that support our immune and nervous systems. — Hannah Goldfield, New Yorker, 29 June 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