Sound1  —n. 1 sensation caused in the ear by the vibration of the surrounding air or other medium. 2 vibrations causing this sensation. 3 what is or may be heard. 4 idea or impression conveyed by words (don't like the sound of that). 5 mere words. —v. 1 (cause to) emit sound. 2 utter, pronounce (sound a warning note). 3 convey an impression when heard (sounds worried). 4 give an audible signal for (an alarm etc.). 5  test (the lungs etc.) By the sound produced.  sound off talk loudly or express one's opinions forcefully.  soundless adj. [latin sonus]