超声（的）
指大多数人听不见的振动频率（通常高于 18 kHz）。更宽泛地说，"超声"一词常用于泛指任何高频振动。
Ultrasonic
Referring to vibration frequencies that cannot be heard by most people (usually greater than 18 kHz). More loosely, the term "ultrasonic" is often used for any high-frequency vibration.