leap second


Definition of leap second 

: 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

Every time the gap is more than 0.9 seconds, an extra second is added to UTC—a leap second—to bring the two back in sync. Peter Bright, Ars Technica, "Windows 10 will get better at telling time with new leap second support," 19 July 2018 Eventually, the effects of tidal friction should overcome all those other factors, and Earth’s days will get longer and longer as its rotation keeps slowing (forcing timekeepers to add leap seconds to the calendar periodically). Brian Resnick, Vox, "The summer solstice is Thursday: 6 things to know about the longest day of the year," 19 June 2018 Ryan Solberg's single got past a leaping second baseman to move Villarreal over from first, but a pop out to center ended the threat. Justin Maskulinski, Houston Chronicle, "The Woodlands takes down Round Rock, advances to state tourney," 1 June 2018 When a leap second was added on a weekend in 2012, huge websites like Mozilla, Reddit and LinkedIn crashed. Noelle Devoe, Seventeen, "Beware the Leap Second: Will Today's Extra Second Break The Internet?!," 30 June 2015 That all seems to make sense, but some people are majorly freaking out about the leap second, because messing with time has historically wreaked havoc on our technology-dependent world. Noelle Devoe, Seventeen, "Beware the Leap Second: Will Today's Extra Second Break The Internet?!," 30 June 2015 But unlike leap years, leap seconds are not predictable in advance. Jay Bennett, Popular Mechanics, "The Centuries-Long Quest to Measure One Second," 24 Mar. 2017 The phenomenon of the leap second, which is designed to control for unpredictable variations in the Earth's rotation. Eric Limer, Popular Mechanics, "There's a New Unit of Time Just for Virtual Reality," 24 Jan. 2018 Felix Pena then walked Zack Cozart before Votto lined an RBI single off the glove of leaping second baseman La Stella, making it 4-2. USA TODAY, "Happ hits 3-run homer in 8th, Cubs beat Reds 5-4," 29 Sep. 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'leap second.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of leap second

1971, in the meaning defined above

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Last Updated

17 Nov 2018

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The first known use of leap second was in 1971

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