The Collaborative International Dictionary of English v.0.48:

Julian \Jul"ian\ (?; 277) a. [L. Julianus, fr. Julius. Cf.
   July, Gillian.]
   Relating to, or derived from, Julius Caesar.
   [1913 Webster]

   Julian calendar, the calendar as adjusted by Julius Caesar,
      in which the year was made to consist of 365 days, each
      fourth year having 366 days.

   Julian epoch, the epoch of the commencement of the Julian
      calendar, or 46 b. c.

   Julian period, a chronological period of 7,980 years,
      combining the solar, lunar, and indiction cycles (28 x 19
      x 15 = 7,980), being reckoned from the year 4713 B. C.,
      when the first years of these several cycles would
      coincide, so that if any year of the period be divided by
      28, 19, or 15, the remainder will be the year of the
      corresponding cycle. The Julian period was proposed by
      Scaliger, to remove or avoid ambiguities in chronological
      dates, and was so named because composed of Julian years.


   Julian year, the year of 365 days, 6 hours, adopted in the
      Julian calendar, and in use until superseded by the
      Gregorian year, as established in the reformed or
      Gregorian calendar.
      [1913 Webster]