expression, noun which may take the genitive case particle 'no'
only once; just once
Emphasizes that something happens or is done a single time and no more. Often used with の to modify a noun.
一度きりの人生だから、後悔しないように生きたい。
Since we only live once, I want to live without regrets.
このチャンスは一度きりだ。
This chance comes only once.
Variant using numeral １; less common in formal writing.
Combination of 一度 (once) and きり (only, just). きり derives from the verb 切る (to cut), implying a cut-off limit.