Saúde
Navigational aid
Texto da Wikipédia (en), licença CC BY-SA. O BETARUBI mostra o verbete inteiro nesta página — a leitura não continua fora do site.
A navigational aid (NAVAID), also known as aid to navigation (ATON), is any sort of signal, markers or guidance equipment which aids the traveller in navigation, usually nautical or aviation travel. Common types of such aids include lighthouses, buoys, fog signals, and day beacons.