一いっ生しょう一いち度ど

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

once in a lifetime; once in one's life

Emphasizes that something is a rare, possibly unique opportunity or experience. Often used with nouns like 機会 (chance) or 体験 (experience).

• 一いっ生しょう一いち度どのチャンスだから、絶ぜっ対たいに逃のがしたくない。

  It's a once-in-a-lifetime chance, so I definitely don't want to miss it.

• 彼かの女じょにとって、それは一いっ生しょう一いち度どの大だい舞ぶ台たいだった。

  For her, it was the biggest stage of her life.