Dictionary of Difficult Words - ultrasonic

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

a. denoting air-waves or vibrations with frequencies higher than those audible to the human ear, i.e. more than about 20,000 cycles per second. ultrasonics, n. study and use of such waves.

Blue stands for the Pacific Ocean and water on which life depends. Yellow symbolizes the sun. Green represents the lush vegetation. Effective date: 18 November 1977. >>