also: ももとせ
hundred years; century; a very long time
Literally 'one hundred years', also used figuratively for an extremely long time. The archaic reading ももとせ is poetic.
この建物は百年以上前に建てられた。
This building was built over a hundred years ago.
百年に一度の大災害と言われている。
It is said to be a once-in-a-century disaster.
そんな日が来るのは百年早いよ。
It'll be a hundred years too soon for that day to come.
百年 simply means a duration of one hundred years, whereas 世紀 refers to a numbered historical century such as the 20th century.
the hundredth year · end of one's rope; out of luck; rare chance; unusually good fortune
centenary; centennial celebration
all year round; always; constantly
100th birthday anniversary
century of humiliation
Standard kanji spelling for 'hundred years' or 'century'.
Rare variant using 歳 (years of age); not the usual spelling for 'century'.
Archaic or poetic reading; rarely used in modern Japanese.
Compound of 百 (hyaku, 'hundred') and 年 (nen, 'year'). The reading ももとせ is an older native Japanese reading of the same kanji.