intercalary

形容词 intercalary:

1. having a day or month inserted to make the calendar year correspond to the solar year: "Feb. 29 is an intercalary day"

in.ter.ca.lar.y

adj.（形容词）

Inserted in the calendar to make the calendar year correspond to the solar year. Used of a day or month.
闰的（闰日、闰年的）：在日历中加入一天或一月而使历年与太阳年相吻合的
Having such a day or month inserted. Used of a year.
闰年的：一年中有闰日或闰月的
Inserted between other elements or parts; interpolated.
插入的：在其他要素或部分中插入的；添加的

来源：
Latin intercal3rius, intercal3ris
拉丁语 intercal3rius, intercal3ris
from intercal3re [to intercalate] * see intercalate
源自 intercal3re [添加] *参见 intercalate