1. (n.) An instrument used in auscultation for examining the organs of the chest, as the heart and lungs, by conveying to the ear of the examiner the sounds produced in the thorax.

2. (v. t.) To auscultate, or examine, with a stethoscope.

attenuator audio-frequency tube ballast regulator ballast tube beam-switching tube convertor current regulator damper detector discriminator doubler ear trumpet electronic hearing aid focus tube generator hard-of-hearing aid hearing aid iconoscope inverter limiter local-oscillator tube megaphone mixer tube modulator multiplier multipurpose tube multivibrator oscillator output tube phase inverter picture tube power tube preamp preamplifier pulse generator radio-frequency tube receiving tube rectifier tube regulator repeater speaking trumpet stethoscope transducer transistor hearing aid trigger tube vacuum-tube hearing aid