Avanaddha Vadya

Meaning: Avanaddha Vadya are those instruments in which the body of the Musical Instrument would be made up of special clay, wood or metal; barrel shaped with both the sides open in the opposite ends e.g., Mrdanga, Pakhawaja, Dholak, Madal etc. either the kettle shaped Musical Drums with only one end opening e.g., Tabla, Bayan, Urdhwaka etc. is covered with best skin with the help of thin and long leather straps to keep the Musical Drum in perfect Tone. 
Avanaddha Vadya is known as MEMBRANOPHONES in western countries. A membranophone is any musical instrument which produces sound primarily by way of a vibrating stretched membrane. Most membranophones are drums. Hornbostel-Sachs divides drums into three main types: struck drums, where the skin is hit with a stick, the hand, or something else; string drums, where a knotted string attached to the skin is pulled, passing its vibrations onto the skin; and friction drums, where some sort of rubbing motion causes the skin to vibrate (a common type has a stick passing through a hole in the skin which is pulled back and forth), (taken from wikipedia)