terminator

noun

ter·​mi·​na·​tor ˈtər-mə-ˌnā-tər 

1

: the dividing line between the illuminated and the unilluminated part of the moon's or a planet's disk

2

: one that terminates

Examples of terminator in a Sentence

Recent Examples on the Web

The moon's immense shadow was also spied by South Korea's GEO-KOMPSAT-2A weather satellite from its perch 22,370 miles (36,000 km) above Earth in geostationary orbit, close to the shadowy line of the night-day terminator. —Anthony Wood, Space.com, 18 Feb. 2026

This is prime time for lunar viewing, with shadows from mountains and craters stretched dramatically close to the terminator — the line between lunar night and day. —Jamie Carter, Forbes.com, 19 Jan. 2026

The amount of time between two terminators—never exactly 11 years—is a strong indicator of the strength of the next cycle, according to the model. —Sarah Scoles, Scientific American, 10 Dec. 2025

On Mercury, the dividing line between day and night, the terminator, is more than just a twilight zone. —Kaif Shaikh, Interesting Engineering, 13 Nov. 2025

Word History

First Known Use

1652, in the meaning defined at sense 2

Rhymes for terminator

• activator
• actuator
• agitator
• alligator
• allocator
• alternator
• animator
• annotator
• applicator
• arbitrator
• aspirator
• aviator