なるほど

interjection, adverb

I see; indeed; that's right

Expresses understanding, agreement, or realization. Often used as an interjection, but can also function adverbially to mean 'indeed' or 'truly'.

• 「このボタンを押おすと動うごくんだよ」「なるほど、そういう仕し組くみか」

  "It works when you press this button." "I see, so that's how it works."