terminator

American

[tur-muh-ney-ter] / ˈtɜr məˌneɪ tər /

noun

a person or thing that terminates.
Astronomy. the dividing line between the illuminated and the unilluminated part of a satellite or planet, especially the moon.

terminator British

/ ˈtɜːmɪˌneɪtə /

noun

the line dividing the illuminated and dark part of the moon or a planet

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of terminator

1760–70; < Late Latin terminātor, equivalent to terminā ( re ) to terminate + -tor -tor

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

It was an emotional triumph—over terminator Tadej Pogacar, no less—for one of cycling’s best.

From The Wall Street Journal • Apr. 13, 2026

Artemis II pilot Victor Glover heard the call of the terminator: the border between the moon’s daytime and nighttime — the lunar dawn.

From Los Angeles Times • Apr. 9, 2026

That frontier between light and darkness is known as the terminator.

From BBC • Apr. 3, 2026

The terminator is the imaginary line that separates the day and night sides of a planet.

From Science Daily • Apr. 5, 2024

I made the Cowardly Lion look like the terminator.

From "Twilight" by Stephenie Meyer

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023