adverb
anciently; formerly; in old times
Adverbial use meaning 'in ancient times' or 'long ago'. Often used in historical or formal contexts.
古くは、この地域は海だった。
In ancient times, this area was a sea.
その習慣は古くから伝わっている。
That custom has been handed down from long ago.
noun
Noun use referring to the distant past. Often appears in set phrases like 古くから.
古くからある神社を訪ねた。
I visited a shrine that has existed since old times.