天てん文もん単たん位い

noun

astronomical unit; AU

A unit of length used in astronomy, roughly the average distance between the Earth and the Sun. Technical term.

• 地ち球きゅうから太たい陽ようまでの距きょ離りは約やく1天てん文もん単たん位いです。

  The distance from the Earth to the Sun is about 1 astronomical unit.