It is believed to have been similar to a violin, but occasionally had only three strings, particularly before the 17th century.
The term was later used as an umbrella for a variety of string instruments.
Many of the instruments within this family contained anywhere from three to eight strings (also double sets of strings like a mandolin), either had frets or did not, was built with either very narrow ribs or wide ribs, and most distinctive of all (at least by modern standards) either did or did not contain sympathetic strings.
According to The New Grove Dictionary of Musical Instruments, one of the earliest inceptions of the term came from G.M.
Lanfranco, a lesser known 16th century Italian composer, who uses the term “violetta” in one of his books titled Scintille di musica in 1533.