A Dictionary of Music and Musicians/Fioriture
FIORITURE, flowerets. The Italian term for ornaments—scales, arpeggios, turns, shakes, etc.—introduced by singers into airs. In the last century airs were often written plain, and were embroidered by the singers according to their taste and ability. Such songs as 'O dolce concento' and 'Nel cor piú' were seldom sung alike by two different singers. Rossini's early airs were written for the same treatment—witness 'Non piú mesta.' A remnant of it many will still remember in the long tasteless cadenzas indulged in at the close of Handel's airs. This was all very well as long as singers were also good musicians, and as long as the singing was more thought of than what was sung. But now these things are changed, and the composer writes exactly what he intends to be sung—notes, nuances, and expression.
The practice of 'fioriture' was not unknown to players in the orchestra as well as to singers. Spohr gives some amusing and almost incredible instances of such freaks of Horns and Clarinets in the Tutti of his 'Scena Cantante' Concerto, at Rome in 1816 (Selbstbiographie, i. 330).