What is tone?
Tone is quality in pitch, harmonic composition and time, exhibiting linear dynamic behavior in the complex intensities of music.
Tone is not how something measures but how it sounds.
The word was made popular (though in its German form, "Tonempfindungen") through Hermann von Helmholtz’s groundbreaking work Sensations of Tone, written well over a century ago.
The correct usage has survived and flourished in the music world, particularly with guitarists.