闰秒

閏秒
rùnmiǎo

leap second

Wiktionary

Entry Composition

1 闰 rùn
  1. intercalary
  2. an extra day or month inserted into the lunar or solar calendar (such as February 29)
2 秒 miǎo
  1. second (unit of time)
  2. arc second (angular measurement unit)
  3. (coll.) instantly