leap second


Also found in: Thesaurus, Acronyms, Encyclopedia, Wikipedia.
Related to leap second: leap year

leap second

n.
A second of time, as measured by an atomic clock, added to or omitted from official timekeeping systems periodically to compensate for small changes in the rotation of the earth and therefore the length of a solar day.

leap second

n
(Units) a second added to or removed from a scale for reckoning time on one particular occasion, to synchronize it with another scale

leap′ sec`ond


n.
an extra second intercalated into the world's timekeeping system about once a year, made necessary by the gradual slowing down of the earth's rotation.
[1970–75]
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.leap second - a second (as measured by an atomic clock) added to or subtracted from Greenwich Mean Time in order to compensate for slowing in the Earth's rotation
s, sec, second - 1/60 of a minute; the basic unit of time adopted under the Systeme International d'Unites
References in periodicals archive ?
A leap second was added most recently on 30 June 2015 at 23:59:60 UTC.
Or I would make the day the leap second falls on an I-pad free day for my kids so that's one extra second they don't get to waste
However, the rotation speed of the Earth fluctuates unpredictably, and has been found to even slow down due to friction caused by the ocean tides -- hence the need for a leap second.
59 Greenwich Mean Time (GMT) on June 30, the earth will experience a minute that will last 61 seconds -- the extra second is called the leap second.
The International Earth Rotation and Reference Systems Service said the leap second was added to account for the small difference in time between the rotation of the globe and the atomic clocks, reports (https://au.
Although leap seconds caused by the need to compensate for the earth's rotation are extremely rare occurrences -- the last whole second adjustment would have happened in 1820 had atomic clocks and NTP servers existed -- there have in fact been 25 leap seconds for other reasons since the beginning of atomically-measured time in 1971.
The so-called leap second was added to electronic clocks at midnight universal time on Saturday, with atomic clocks reading 23 hours, 59 minutes and 60 seconds before then moving on to Greenwich Mean Time.
Leap second to be inserted to adjust for earth's rotation
For accuracy, it adds a leap second to the year when necessary, making the last minute of June or December 61 seconds long instead of the usual 60.
The leap second is actually aimed at midnight, Greenwich Mean Time.
AGI Keeps Its Software Users In Synch By Accounting For Upcoming Leap Second
Each time those added milliseconds approach a full second, scientists add a leap second to atomic clocks.