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

Recent projections suggest that the need for a negative leap second is likely to hit before 2035. — Emma Gometz, Scientific American, 8 July 2026

The system of leap seconds was introduced in the 1970s, according to Time and Date. — Julia Jacobo, ABC News, 22 July 2025

Since 1972, 27 leap seconds have been added, with the last one having been added in 2016. — Sara Hashemi, Smithsonian Magazine, 22 July 2025

The prospect of a negative leap second raises concerns because there are still ongoing problems with positive leap seconds after 50 years, explained Levine. — Jacopo Prisco, CNN Money, 21 July 2025

Word History

First Known Use

1971, in the meaning defined above

Rhymes for leap second

• beckoned
• reckoned
• seconde
• femtosecond
• microsecond
• millisecond
• nanosecond
• picosecond