Viola
Col Legno: translating to ‘with the wood’ from Italian, this instructs musicians to turn the bow over to use the stick rather than the hair.
There are two types of this technique:
Col Legno Battuto - tapping or striking the string with the stick. This creates a dry, percussive sound, and is often used to create an eerie texture, a well-known example being the Finale from Berlioz’s Symphonie Fantastique.
Col Legno Tratto - drawing or dragging the stick across the string. This technique creates a wispy and airy sound.