1. The primary or most important department within an organization, company, or institution
The departamento principal handles all strategic decisions for the company.
O departamento principal gerencia todas as decisões estratégicas da empresa.
2. In real estate, a primary or master apartment/unit in a residential building
They rented the departamento principal of the building with access to all facilities.
Alugaram o departamento principal do prédio com acesso a todas as instalações.