This is the 6086th most frequent Dutch word.
romeinen
"Romeinen" means "Romans" in English.
Here, 'Romeinen' refers to the ancient Roman people as a collective noun.
De Romeinen bouwden indrukwekkende aquaducten.
The Romans built impressive aqueducts.
In this sentence, 'Romeinen' is used to identify the subject of the book, again pertaining to the Roman people.
Ik las een boek over de gewoontes van de Romeinen.
I read a book about the habits of the Romans.
Here, 'Romeinen' represents the historical culture and people of ancient Rome, as understood from studies.