In radio, longwave refers to parts of the radio spectrum with relatively long wavelengths. The term is a historic one dating from the early 20th century, when the radio spectrum was considered to consist of long, medium and short wavelengths. Most modern radio systems and devices use wavelengths which would then have been considered 'ultra-short'.

In radio, longwave refers to parts of the radio spectrum with relatively long wavelengths. The term is a historic one dating from the early 20th century, when the radio spectrum was considered to consist of long, medium and short wavelengths. Most modern radio systems and devices use wavelengths which would then have been considered 'ultra-short'.