rinforzando
A sudden increase in volume on a note or short passage. Abbreviated as rfz.
In Depth
Rinforzando (abbreviated rfz or rinf.) means reinforcing — a sudden, strong emphasis on a note, chord, or short passage. It is more sustained than sforzando (sfz), which is a sharp accent on a single note. Rinforzando suggests a brief surge of intensity rather than a momentary jab.
The distinction between rinforzando, sforzando, and other accent markings is subtle and sometimes used inconsistently by composers. Generally, rinforzando implies that a short passage (not just one note) should be played with increased force and emphasis. It creates a brief brightening of intensity within the musical texture before the prevailing dynamic resumes.
Beethoven sometimes wrote both sfz and rfz in the same passage to indicate different degrees of accent — a level of dynamic precision that few other composers have attempted.