うるう

noun, noun which may take the genitive case particle 'no'

leap; intercalary; embolism

Refers to the insertion of an extra day, month, or similar unit into a calendar to keep it aligned with astronomical events. Most commonly seen in compounds like うるう年 (leap year) and うるう秒 (leap second).

• 今年ことしはうるう年どしなので、2月がつが29日かまである。

  This year is a leap year, so February has 29 days.

• うるう秒びょうが挿そう入にゅうされるのは、地ち球きゅう