1.
once; if/when once; the moment that
A literary adverb meaning 'once' in the sense of 'once (something happens)' — used in conditional or temporal clauses to set up a consequence that follows from a single occurrence. Has a written, formal tone.
An alternate, literary reading of 一度. Where いちど means 'one time' in counting terms, ひとたび is always adverbial and conditional in flavor — 'once X happens, then Y'.
Common patterns
- 一度…ば / たら: once… (if/when once)
- 一度…と: the moment (something happens)
Register: Strongly literary. Common in essays, speeches, and proverb-like statements; uncommon in casual conversation, where the spoken equivalent would be ⌜一度…たら⌟ or ⌜いったん…たら⌟.
Similar words
- 一度: once, one time — neutral, can be a literal count
- いったん: once, for the moment — closer to ひとたび in the conditional sense, more conversational
- 一たび: mixed kana form occasionally seen in older writing