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.
The crescent is a symbol of Islam and the green also denotes Islam. The four stars and the four stripes of colour represent the four islands in the group (including Mayotte, which is a French dependency). Effective date: 2002.