This is the 2607th most frequent Dutch word.
hierin
"Hierin" means "in this" or "in here" in English.
"Hierin" acts as a reference to the location mentioned earlier where the key is situated.
Hierin ligt de sleutel tot het huis.
Herein lies the key to the house.
"Hierin" refers to the notebook, indicating that it will contain the ideas.
Ik heb dit schrift gekocht, en hierin zal ik mijn ideeën opschrijven.
I bought this notebook, and herein I will write down my ideas.
"Hierin" refers to the entity or object where the secret is contained.