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

At the group’s last meeting in 2022, member countries voted in favor of a resolution that called for a plan to phase out the leap second on or before 2035. — Katie Hunt, CNN Money, 13 Oct. 2026

But the prospect of the first negative leap second poses an even greater risk. — Harriet Marsden, TheWeek, 13 Oct. 2026

If Earth keeps up this faster rotation, timekeepers might eventually need to introduce the first-ever negative leap second. — Vahe Peroomian, The Conversation, 8 Oct. 2026

Word History

First Known Use

1971, in the meaning defined above

Rhymes for leap second

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