relating to or denoting sound waves with a frequency below the lower limit of human audibility. The deepest rumbling sounds that are way below the sounds that human ears can detect.

The unit that scientists use to measure the pitch, or frequency of sound. The lowest frequency a person can hear is 20 hertz. The highest frequency a person can hear is 20,000 hertz.

Structure of the body.

without conscious thought or attention; spontaneously.

Frequencies above 20,000 Hz. When your dog tilts his head to listen to seemingly imaginary sounds, he is tuning in to ultrasonic frequencies, as high as 45,000 Hz.

Sources such as books, magazines, or newspaper articles.

the quality of a sound governed by the rate of vibrations producing it; the degree of highness or lowness of a tone.

Copy a person’s speech.

the number of times per second that a sound pressure wave repeats itself.

the quality or state of being different or diverse; the absence of uniformity, sameness, or monotony.

Sources that use computer technology such as a Website.

To pay close attention to visual details.

sound waves with frequencies below the lower limit of human audibility; a sound too low for humans to hear.

so clearly apparent as to be unmistakable; readily distinguishable by the senses

the act of allowing something to escape

To move back and forth

the quality or state of having different forms or types