responder
//rɪˈspɒndər//
Noun
responderSingular
respondersPlural
1
A person who replies or reacts to something, especially someone who answers a survey, questionnaire, or inquiry.
Over 500 responders completed the online survey.
2
A person trained to provide emergency assistance, such as a paramedic, firefighter, or police officer who arrives at the scene of an incident.
First responders arrived at the accident scene within minutes.
3
A device or system that automatically transmits a signal in response to receiving a specific signal or stimulus.
The aircraft's transponder acts as a responder, automatically sending identification signals to radar systems.