An oriscus is a type of
neume
A neume (; sometimes spelled neum) is the basic element of Western and Eastern systems of musical notation prior to the invention of five-line staff notation.
The earliest neumes were inflective marks that indicated the general shape but not nec ...
found in
gregorian chant
Gregorian chant is the central tradition of Western plainsong, plainchant, a form of monophony, monophonic, unaccompanied sacred song in Latin (and occasionally Greek (language), Greek) of the Roman Catholic Church. Gregorian chant developed ma ...
.
It is a single neume, meaning it represents one pitch, unlike a compound neume, representing a sequence of more than one pitch.
It is considered an ornamental neume, like the
strophicus,
quilisma,
salicus, and
pressus, but the original meaning of the ornament is unclear. It is usually found added to another neume as an auxiliary note. Some modern chant editions replace the sign with a regular
punctum.
It is found in the chant manuscripts of St. Gall, Northern Spain, Catalonia, Bologna, Breton, England, Metz, and Aquitaine, but not in those of Toledo. Wagner suggested the neume involved intervals of less than a
semitone
A semitone, also called a half step or a half tone, is the smallest musical interval commonly used in Western tonal music, and it is considered the most dissonant when sounded harmonically.
It is defined as the interval between two adjacent no ...
(i.e.
microtone), but other scholars dispute this. For Cardine, it implied tension on the following note.
[{{cite book, last=Cardine, first=E., title=Semiologia gregoriana, year=1970, publisher=Solesmes]
The name is possibly derived from the Greek ''horos'' "limit" or ''oriskos'' "little hill."
References
Musical notation