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

/ trăn-spŏn′dər /

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

“This transponder that Nokia uses, it’s like a celebrity,” says Mr Verheul, explaining how the kit is booked up for use at various locations in advance.

From BBC

Many of these ships turn off their locational transponders and cross secretly into Argentine waters.

From Los Angeles Times

The Nez Perce Tribe and the Confederated Tribes of the Umatilla Indian Reservation also responded and helped by collecting and scanning transponders on the dead fish.

From BBC

His group has developed a partially automated system called PsyCoP that uses transponders implanted in the animals’ necks, along with cameras and sensors in their cages, to monitor mice as they perform 11 behavioral tests.

From Science Magazine

Minutes later, the plane’s transponder — a communication system that transmits the plane’s location to air traffic control — shut down.

From Seattle Times