antimatter

noun

an·​ti·​mat·​ter ˈan-tē-ˌma-tər  ˈan-ˌtī- 

: matter composed of antiparticles

Examples of antimatter in a Sentence

Recent Examples on the Web

Caltech researchers have created cold molecules containing the radioactive element radium for the first time, opening a new way to investigate why the universe is made mostly of matter instead of equal parts matter and antimatter. — Neetika Walter, Interesting Engineering, 17 July 2026

The theory cannot account for dark matter and offers no explanation for why the universe is made almost entirely of matter rather than equal parts matter and antimatter. — Florencia Canelli, Scientific American, 1 July 2026

This is akin to what happens when an electron meets its antimatter counterpart, or positron. — Robert Lea, Space.com, 21 June 2026

Matter is so dominant in our universe that any antimatter typically encounters matter quickly and annihilates. — Quanta Magazine, 15 June 2026

Word History

First Known Use

1934, in the meaning defined above

Rhymes for antimatter

• atter
• batter
• blatter
• catarrh
• chatter
• clatter
• fatter
• flatter
• hatter
• latter
• matter
• natter

Kids Definition

antimatter

noun

an·​ti·​mat·​ter ˈant-i-ˌmat-ər 

: matter whose parts match parts of ordinary matter except in having some opposite properties (as a positive instead of a negative charge)