A Dictionary of Music and Musicians/Rinforzando
Appearance
RINFORZANDO, 'reinforcing' or increasing in power. This word, or its abbreviations, rinf. or rfz. is used to denote a sudden and short-lasting crescendo. It is applied generally to a whole phrase however short, and has the same meaning as sforzando, which is only applied to single notes. It is sometimes used in concerted music to give a momentary prominence to a subordinate part, as for instance in the Beethoven Quartet, op. 95, in the Allegretto, where the violoncello part is marked rinforzando, when it has the second section of the principal subject of the movement.
[ J. A. F. M. ]