Bel canto (Italian for "beautiful singing" or "beautiful song", ˈbɛl ˈkanto)—with several similar constructions (bellezze del canto, bell'arte del canto)—is a term with several meanings that relate to Italian singing. The phrase was not associated with a "school" of singing until the middle of the 19th century, when writers in the early 1860s used it nostalgically to describe a manner of singing that had begun to wane around 1830. Nonetheless, "neither musical nor general dictionaries saw fit to attempt [a] definition [of bel canto] until after 1900". The term remains vague and ambiguous in the 21st century and is often used to evoke a lost singing tradition. As generally understood today, the term bel canto refers to the Italian-originated vocal style that prevailed throughout most of Europe during the 18th and early 19th centuries. Late 19th- and 20th-century sources "would lead us to believe that bel canto was restricted to beauty and evenness of tone, legato phrasing, and skill in executing highly florid passages, but contemporary documents [those of the late 18th and early 19th centuries] describe a multifaceted manner of performance far beyond these confines." The main features of the bel canto style were: prosodic singing (use of accent and emphasis) matching register and tonal quality of the voice to the emotional content of the words a highly articulated manner of phrasing based on the insertion of grammatical and rhetorical pauses a delivery varied by several types of legato and staccato a liberal application of more than one type of portamento messa di voce as the principal source of expression (Domenico Corri called it the "soul of music" – The Singer's Preceptor, 1810, vol. 1, p. 14) frequent alteration of tempo through rhythmic rubato and the quickening and slowing of the overall time the introduction of a wide variety of graces and divisions into both arias and recitatives gesture as a powerful tool for enhancing the effect of the vocal delivery vibrato primarily reserved for heightening the expression of certain words and for gracing longer notes.