Final answer:
The piano, known historically as the pianoforte, gets its name from Italian words signifying its ability to play notes at varying volumes, from soft to loud.
Step-by-step explanation:
The instrument that derives its name from the Italian word for "soft-loud" is the pianoforte, commonly shortened to piano. The name reflects the instrument's ability to produce a range of dynamics, from soft (piano) to loud (forte). Its creation is attributed to Bartolomeo Cristofori around the early 18th century. The piano's dynamic range comes from the way a player presses the keys, which in turn causes hammers to strike the strings with varying degrees of force to produce sound.
This unique feature distinguished it from the harpsichord, which plucks strings and cannot dynamically change the volume of the sound produced based on how the keys are struck. The piano has since become an essential instrument in both classical and contemporary music due to its versatility and dynamic expressiveness.