1. Additional troops or military support sent to strengthen a military force
The general requested reinforcements to defend the fortress.
O general solicitou reforços para defender a fortaleza.
2. Additional support, help, or resources provided to strengthen something
The company sent reinforcements to the struggling department.
A empresa enviou reforços para o departamento que estava em dificuldades.
3. Materials or structures added to strengthen something
Steel reinforcements were added to the concrete foundation.
Reforços de aço foram adicionados à fundação de concreto.