How to say "century" in Japanese

• 世紀せいきJLPT N3approx.Common
  nounThe default word for a century as a historical period of a hundred years, used in dates, history, and counting. For the ordinary 'century' of time reckoning, this is the word you want.
  彼かれは１９世紀せいきに生うまれた。↗

  He was born in the 19th century.
• センチュリー
  nounA katakana loanword meaning 'century'. It is less common than 世紀 and is seldom the word you want for the historical period; learners can safely pass it over in favor of 世紀.
• 一世紀いっせいき
  nounMeans 'one century' — a single full span of a hundred years. It is less common than 世紀, which is the usual choice for naming or counting centuries in dates and history.
  １世紀せいきは１００年ねんです。↗

  A century is one hundred years.
• 百年ひゃくねん
  nounLiterally 'hundred years'; it can render 'century', but its core sense is the round number of years, and it also means 'a very long time'. For the historical period, 世紀 is the usual choice.

Use 世紀 for the ordinary historical sense of 'century'; 一世紀 and 百年 stress a full hundred-year span (百年 also means 'a very long time'), while 「センチュリー」 is a less common loanword.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 世紀せいきcentury
• センチュリーcentury
• 一世紀いっせいきcentury
• 百年ひゃくねんcentury