noun, adverb, noun which may take the genitive case particle 'no'
long period; long term; extended period
Used as a noun, adverbially, or with の to modify nouns. Often appears in contexts like storage, planning, absence, or sustained effort.
この薬は長期間保存できます。
This medicine can be stored for a long period.
長期間の計画が必要だ。
A long-term plan is necessary.
彼は長期間海外に住んでいた。
He lived abroad for an extended period.