transponder

Or tran·spon·dor

[tran-spon-der]

noun

1. a radio, radar, or sonar transceiver that automatically transmits a signal upon reception of a designated incoming signal.

transponder

/ trænˈspɒndə /

noun

1. a type of radio or radar transmitter-receiver that transmits signals automatically when it receives predetermined signals

2. the receiver and transmitter in a communications or broadcast satellite, relaying received signals back to earth

transponder

1. A radio or radar transmitter and receiver that responds to an incoming signal either by broadcasting its own predetermined signal (as in aircraft identification systems) or by relaying the incoming signal at a different frequency (as in satellite communications).

Word History and Origins

Origin of transponder¹

First recorded in 1940–45; trans(mitter) + (res)ponder

Word History and Origins

Origin of transponder¹

C20: from _transmitter + _responder

Example Sentences

Collision-avoidance systems on commercial jets typically use a mix of transponders and other sensors, but not radar.

Read more on The Wall Street Journal

The Los Angeles County Metropolitan Transportation Authority said it doesn’t anticipate a significant uptick in the number of FasTrak transponders being issued as a consequence of the decal program’s end.

Read more on Los Angeles Times

Estonian media are reporting that in the latest incident the Russian jets had their transponders switched off.

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“He didn’t call, he didn’t radio. When we looked at where his transponder was, he was already down in Oregon. At that point, it was obvious something was badly wrong.”

Read more on Los Angeles Times

The transponder's code was for a dangerous load, he told the BBC, and that air refuelling had taken place over the Atlantic.

Read more on BBC