1. A door that is not the main or primary entrance to a building or room; an auxiliary or supplementary entrance
The secondary door leads to the back garden.
A porta secundária leva para o jardim dos fundos.
2. In architecture or building design, a door of lesser importance than the main entrance
The office building has a secondary door for emergency exits.
O prédio de escritórios tem uma porta secundária para saídas de emergência.