1. To strengthen or add additional support to defensive positions, structures, or strategies to make them more resistant to attack or failure
The military decided to reinforce defense along the border with additional troops.
O exército decidiu reforçar a defesa na fronteira com tropas adicionais.
2. To improve protective measures against threats or vulnerabilities
We need to reinforce defense mechanisms in our cybersecurity system.
Precisamos reforçar os mecanismos de defesa no nosso sistema de segurança cibernética.