leap second
noun
: an intercalary second added to Coordinated Universal Time to compensate for the slowing of the earth's rotation and keep Coordinated Universal Time in synchrony with solar time
Examples of leap second in a Sentence
Recent Examples on the Web
While there have been dozens of positive leap seconds, in which a second was added, there has never been a negative leap second.
—
Julia Jacobo, ABC News, 22 July 2025
And that’s with a positive leap second, which has been done over and over.
—Jacopo Prisco, CNN Money, 21 July 2025
Some scientists predict that if Earth's rotation continues to speed up by just a few more milliseconds each year, a negative leap second might be needed around 2029, according to BBC Sky at Night Magazine, though the exact timing depends on future measurements.
—Daisy Dobrijevic, Space.com, 10 July 2025
To date, all adjustments to time have involved adding a leap second.
—Alice Gibbs, MSNBC Newsweek, 10 July 2025
See All Example Sentences for leap second
Examples are automatically compiled from online sources to
show current usage.
Read More
Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
Send us feedback.
Julia Jacobo, ABC News, 22 July 2025
And that’s with a positive leap second, which has been done over and over.
—Jacopo Prisco, CNN Money, 21 July 2025
Some scientists predict that if Earth's rotation continues to speed up by just a few more milliseconds each year, a negative leap second might be needed around 2029, according to BBC Sky at Night Magazine, though the exact timing depends on future measurements.
—Daisy Dobrijevic, Space.com, 10 July 2025
To date, all adjustments to time have involved adding a leap second.
—Alice Gibbs, MSNBC Newsweek, 10 July 2025
See All Example Sentences for leap second
Cite this Entry
“Leap second.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/leap%20second. Accessed 3 Nov. 2025.
Copy CitationLove words? Need even more definitions?
Merriam-Webster unabridged
Share