Examples from the Web for bissextile
This fourth year was denominated Bissextile, because the sixth day before the Kalends of March was reckoned twice.Letters on Astronomy|Denison Olmsted
Can we therefore believe that the Egyptians before this period were ignorant of the bissextile intercalation?
The bissextile is known to have been used by the Mayas, Tzendals, and Quichés, and it was probably common.Ancient America, in Notes on American Archaeology|John D. Baldwin
The fourth year was bissextile, and the dominical letters were F, E; the following year D, and so on.