What is the meaning of 'una corda' in piano performance?

'Una corda' is an Italian term that translates to "one string," and it refers to the left or soft pedal located on a piano. When this pedal is pressed, the action of the piano shifts so that the hammers strike only one string for each note (in the case of the treble), rather than the usual two or three. This results in a softer and warmer tone.

In performance, using the una corda pedal allows the pianist to achieve a delicate sound, which is particularly useful for expressive passages that require subtlety and nuance. The term itself is an instruction for the pianist to evoke this softer timbre, thus defining its meaning in the context of musical interpretation and technique.