How is the term "sonoro" best defined?

The term "sonoro" is best defined as "resonant, with rich tone." In music, this term is used to describe a quality of sound that is full, vibrant, and has a certain warmth. When a note or passage is marked as sonoro, it suggests that the performer should produce a sound that is not only audible but also has a pleasing and rounded character, enhancing the musical experience.

This definition captures the essence of musical expression that involves both clarity and depth, encouraging the use of resonance to enrich the overall tone of the piece. In contrast, the other definitions do not align with the specific characteristics intended by "sonoro." For instance, sudden silence, detached sound, and softly do not convey the fullness and richness that "sonoro" specifically denotes.