Plain English Meaning
A way of using a radio where you talk on one frequency and listen on another, so both sides can speak at once instead of taking turns.
Full Definition
A radio communication mode in which transmitting and receiving occur on two different frequencies, allowing both stations to send and receive at the same time without interfering with each other.
Context Anchor
Seen in navigation and communication equipment discussions when comparing how aircraft radio systems send and receive signals.
Derivation
From the Latin 'duplex,' meaning 'twofold' or 'double.' The term reflects the use of two separate frequencies — one for each direction of the conversation.
Why Pilots Care
It supports continuous two-way contact without waiting to between and receive, which is essential in busy .