• WordNet 3.6
    • adj intercalary having a day or month inserted to make the calendar year correspond to the solar year: "Feb. 29 is an intercalary day" "a leap year is an intercalary year"
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Webster's Revised Unabridged Dictionary
    • Intercalary (Chron) Inserted or introduced among others in the calendar; as, an intercalary month, day, etc.; -- now applied particularly to the odd day (Feb. 29) inserted in the calendar of leap year. See Bissextile n.
    • Intercalary Introduced or inserted among others; additional; supernumerary. "Intercalary spines.""This intercalary line . . . is made the last of a triplet."
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Century Dictionary and Cyclopedia
    • intercalary In chronology, inserted in the calendar out of regular order, as an extra day or month; having an additional day or month, as one of a cycle of years. The lunar reckoning and other features of the Greek, Roman, and other ancient calendars made the year of twelve months too short, and intercalary days and months were officially added at intervals to adjust the difference. Since the reformation of the calendar by Julius Cæsar, in 46 b. c., only one intercalary day in every fourth year, or leap-year, has been required, the 29th of February.
    • intercalary Hence Inserted or coming between others; introduced or existing interstitially: as, intercalary beds in geology.
    • intercalary In biology, intermediate in character between two types, yet not representing the actual genetic passage from one form to the other; interposed or intercalated, yet not biologically transitional.
    • intercalary In medicine, the days intervening between the critical days or crises of a disease.
    • intercalary In anatomy, additional; supernumerary; inserted between other parts, as the cartilages on the dorsal side of the vertebral column in many elasmobranchs.
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Chambers's Twentieth Century Dictionary
    • adjs Intercalary inserted between others
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Webster's Revised Unabridged Dictionary
L. intercalaris, intercalarius,: cf. F. intercalaire,. See Intercalate
Chambers's Twentieth Century Dictionary
L. intercalāre, -ātuminter, between, calāre, to call. See Calends.


In literature:

But to quit this episode, and to return to my intercalary year of happiness.
"Confessions of an English Opium-Eater" by Thomas De Quincey
For whose behoof mainly a loose intercalary Chapter may be thrown together here.
"History of Friedrich II. of Prussia, Vol. XIX. (of XXI.) Frederick The Great--Friedrich Like to be Overwhelmed in The Seven-Years War--1759-1760" by Thomas Carlyle
Something, however, was arranged in those intercalary moments between the raising of the glasses.
"Castle Richmond" by Anthony Trollope
Hence it is that they are now singing intercalary pieces, a practice first introduced by Agathon.
"The Poetics" by Aristotle
But, when intercalary days in certain years are allowed for, the mean year consists of 354 11/30 days.
"Rambles and Recollections of an Indian Official" by William Sleeman
The second, 7/29, gives seven intercalary days in twenty-nine years, and errs in defect, as it supposes a year of 365 days 5 hours 47 min.
"Encyclopaedia Britannica, 11th Edition, Volume 4, Part 4" by Various
Posterior intercalary: in Diptera, is one of the anal veins (Comst.).
"Explanation of Terms Used in Entomology" by John. B. Smith
"History Of Friedrich II. of Prussia Frederick The Great--Complete Table of Contents: 22 Volumes" by Thomas Carlyle
In intercalary years the first seven months commence one day later.
"Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 3" by Various
The public is requested to consider the Preface as the Second Intercalary Day, for the sake of symmetry.
"Hesperus or Forty-Five Dog-Post-Days Vol. I." by Jean Paul Friedrich Richter

In science:

How can we help future generations prepare for that recoupling now? Alternative schemes involving very infrequent intercalary adjustments (such as a leap minute or leap hour) cannot be credibly presumed to work once short-term adjustments are formally abolished.
The Colloquium on Decoupling Civil Timekeeping from Earth Rotation
For those who favor the decoupling from Earth rotation, “flexible software” should not assume that UT1-UTC is bounded in the future. For those respecting the current system, “flexible software” maintains the necessary infrastructure to accommodate small intercalary adjustments past, present, and future.
The Colloquium on Decoupling Civil Timekeeping from Earth Rotation
Although extended predictions of UT1-UTC might help some software applications, software issues are primarily caused by complete ignorance of intercalary adjustments, rather than a need for their predictable forecast.
The Colloquium on Decoupling Civil Timekeeping from Earth Rotation