1. The primary or central component of a system, device, or organization
The main unit of the air conditioning system is located on the roof.
A unidade principal do sistema de ar condicionado está localizada no telhado.
2. The largest or most important section of a military formation or organization
The main unit advanced while smaller detachments flanked the enemy.
A unidade principal avançou enquanto destacamentos menores flanqueavam o inimigo.
3. The central processing device in a computer or electronic system
The main unit must be connected to a power source before operation.
A unidade principal deve estar conectada a uma fonte de energia antes da operação.