Use it in a sentence ;> Since there is no such word you might need to explain a little more what you are looking for. A transponder is a two-way radio if that helps.
transponder
[tran(smitter) + (re)sponder.]
n : electrical device designed to receive a specific signal and automatically transmit a specific reply
"Transpond wait time" in some systems is the parameter set in the interrogator telling it how long to wait for a valid reply from the transponder. Depending on the system set up it will retry the query a set number of times before sending an alarm to the operator.
I hope I said that right. Radar school was many years ago.
Kenwood uses the term "Transpond" to signify a mobile or portable radio acknowleging a call alert or page. When it receives the alert, it will "reply" back with a tone so the dispatcher knows it was received. Motorola simply calls it an acknowlege.