1. A system of symbols, letters, or numbers used to communicate messages in a way that conceals their meaning from unauthorized persons
The spies used secret codes to communicate with headquarters.
Os espiões usavam códigos secretos para se comunicar com a sede.
2. A hidden sequence or combination used to gain access to restricted information or areas
He entered the secret code to unlock the vault.
Ele inseriu o código secreto para abrir o cofre.
3. Programming instructions or algorithms not meant to be discovered by users
The developer left secret codes in the video game for Easter eggs.
O desenvolvedor deixou códigos secretos no videogame para ovos de páscoa.