Definition of intercalary in English:


Pronunciation /ɪnˈtəːkəl(ə)ri//ˌɪntəˈkal(ə)ri/


  • 1(of a day or a month) inserted in the calendar to harmonize it with the solar year, e.g. 29 February in leap years.

    ‘eighteen months of twenty days each and five intercalary days’
    • ‘He added two extra intercalary months apart from the one regular intercalary month to the year 46 BC.’
    • ‘The intercalary month by which the Arabs adjusted the lunar months to the solar year is abolished, severing the connection between the religious rituals and the seasons.’
    • ‘In the old calendar, an intercalary month of 22 or 23 days called Mercedonius was inserted after the Festival of Terminalia in every other year or as needed.’
    • ‘Chinese mythology holds that disasters always strike in intercalary Augusts and Cheng was aware of the power of this superstition when he wrote his book.’
    • ‘In ancient Egypt, for civil purposes, a solar calendar of 365 days to the year was used in which there were 12 months of 30 days and 5 intercalary days.’
    1. 1.1 Of the nature of an insertion.
      ‘elaborate intercalary notes’
  • 2(of an academic year or period) additional to the standard course and taken at a different institution.

    ‘the intercalary year is taken between the second and final years’
  • 3Botany
    (of the meristem of a plant) located between its daughter cells, especially (in a grass) at or near the base of a leaf.

    • ‘However, the intercalary meristem is considerably longer when considering the leaf extension zone.’
    • ‘In these stems and leaves with intercalary meristems, the upward transpiration stream clearly bypassed most of the enlarging cells.’
    • ‘Leaves are formed from an intercalary meristem which is positioned within the leaf sheaths of subtending leaves.’
    • ‘The second intercalary meristem gives rise to the internode.’
    • ‘Cell division occurs mainly at the intercalary meristem at the base of the internode, but also throughout the internode at early stages of internode development.’


Early 17th century: from Latin intercalarius, from intercalare (see intercalate).