Perdendosi
Losing itself — becoming softer and less defined.
What it means
Perdendosi means “losing itself” and calls for the sound to become weaker and at the same time less defined. Alongside the decrease in volume it resonates that the music loses its contour: the outlines of the phrase dissolve, often connected with a slackening of the tempo.
The marking belongs to the group of words for dying away, which also includes morendo, smorzando, and calando. There is no binding difference between them. Where a distinction is made at all, calando counts as the most matter-of-fact, morendo and smorzando as the words for an extinguishing, and perdendosi as the one that stresses the dissolution of the shape — not merely softer, but as it were vanishing.
In the notation
The word stands in italics above or below the staff and applies until the end of the section; a decrescendo hairpin or a dashed continuation line can be added. Like the related markings, it stands almost exclusively at endings, so that a marking ending it is usually absent.
Musical use
The instruction is used at the end of movements and pieces that are not to conclude but to vanish, and with repeated figures that lose themselves in the distance. In the piano and song literature of the nineteenth century it is widespread; it also appears in orchestral music where a sound seems to step out of the room. The impression often additionally arises from the movement thinning out and voices dropping away.
Tempo and volume decrease together, until the sound gradually disappears. The marking is related to morendo and smorzando and is abbreviated as perd.
Performance practice
Connect the reduction of volume with a pulling back of articulation: less distinct contours belong to the picture here. Pace the decrease over the whole stretch and keep reserve for the last notes. Take care that the tone still carries and the intonation is right. And let the ending remain open, instead of placing it — the instruction calls for a vanishing, not an end.