noun
Refers to a single generation or the span of a person's life. Often used in historical or biographical contexts.
彼は一世を風靡した作家だ。
He was a writer who dominated his generation.
一世一代の大
He accomplished the great work of a lifetime.
noun
the age; the times
Refers to a particular era or period in history. Often used in set phrases like 一世の名君 (a great ruler of the age).
彼は一世の名君と称えられた。
He was praised as a great ruler of the age.
noun, noun, used as a suffix
Used as a suffix after a name to indicate 'the first', as in monarchs or popes. Equivalent to 'I' in English.
エリザベス一世はイギリスの女王だった。
Elizabeth I was the queen of England.
noun
issei; first-generation immigrant
Specifically refers to first-generation Japanese immigrants (or by extension Korean, etc.) abroad. Often used in the context of Japanese-American history.
彼の祖父は一世としてアメリカに渡った。
His grandfather went to America as a first-generation immigrant.