Which term indicates a muted sound produced by hand?

The term that indicates a muted sound produced by hand is "Chiuso." In string instrument terminology, "Chiuso" refers to playing with the hand (often the palm) muted against the strings, leading to a softer, more subdued sound. This technique is commonly used to create a specific timbre or character in the music.

As for the other terms:

• "Smorzando" refers to gradually dying away or fading out, often indicating a softening of volume and intensity, but it does not specifically denote a muted sound created by hand.

• "Sul ponticello" describes playing very close to the bridge of the instrument, which produces a sharp, scratchy sound, rather than a muted effect.

• "Con sord" or "con sordino" indicates the use of a mute to dampen the sound produced by the instrument, which is not the same as muting with the hand directly on the strings.

Thus, "Chiuso" is the most appropriate choice for indicating a muted sound produced by hand.