Naad

A hearable sound is called naad. The sound which is produced by any medium, reaches and recognized by the ear is ‘naad’. The naad can be produced by three facts: -

By the striking of two objects: Sound of Tabla, Sitar, Benjo, Piano etc.
By the rubbing of two objects: Sound of Violin, Sarangi etc.
By passing one object in to another one: Sound of Harmonium, Flute, Mouth organ etc.

Sound is a mechanical wave that is an oscillation of pressure transmitted through a solid, liquid, or gas, composed of frequencies within the range of hearing.  Sound also travels through plasma. a sound effect is a sound recorded and presented to make a specific storytelling or creative point without the use of dialogue or music. The term often refers to a process applied to a recording, without necessarily referring to the recording itself. In professional motion picture and television production, dialogue, music, and sound effects recordings are treated as separate elements. Dialogue and music recordings are never referred to as sound effects, even though the processes applied to them, such as reverberation or flanging effects, often are called "sound effects".