An adverb meaning 'so to speak' or 'as it were', used to rephrase or illustrate an idea.
彼の説明は、いわば現代版の物語だ。
His explanation is, so to speak, a modern version of a story.
このプロジェクトは、いわば会社の将来をかけた挑戦だ。
This project is, as it were, a challenge that stakes the company's future.
彼女はいわばチームの潤滑油のような存在だ。
She is, so to speak, the lubricant of the team.