A course is a pair or more of adjacent strings tuned to unison or an octave and usually played together as if a single string. It may also refer to a single string normally played on its own on an instrument with other multi-string courses, for example the bass string on a nine string baroque guitar.

An instrument with at least one (multiple string) course is referred to as coursed, while one whose strings are all played individually is uncoursed.

Instruments that use two-string courses include:

• Bouzouki
  Bouzouki
  The bouzouki , is a musical instrument with Greek origin in the lute family. A mainstay of modern Greek music, the front of the body is flat and is usually heavily inlaid with mother-of-pearl. The instrument is played with a plectrum and has a sharp metallic sound, reminiscent of a mandolin but...
  
  
• Twelve-string guitar
• Baroque guitar
  Baroque guitar
  The Baroque guitar is a guitar from the baroque era , an ancestor of the modern classical guitar. The term is also used for modern instruments made in the same style....
  
  
• Eight-string bass guitar
• Lute
  Lute
  Lute can refer generally to any plucked string instrument with a neck and a deep round back, or more specifically to an instrument from the family of European lutes....
  
  
• Mandolin
  Mandolin
  A mandolin is a musical instrument in the lute family . It descends from the mandore, a soprano member of the lute family. The mandolin soundboard comes in many shapes—but generally round or teardrop-shaped, sometimes with scrolls or other projections. A mandolin may have f-holes, or a single...
  
  
• Saz
  Baglama
  thumb|180px|Cura and bağlamaThe bağlama is a stringed musical instrument shared by various cultures in the Eastern Mediterranean, Near East, and Central Asia....
  
  
• Springtime
  Springtime (guitar)
  The Springtime is an experimental electric guitar with seven strings and three outputs. The instrument was created in 2008 by Dutch luthier Yuri Landman for guitar player Laura-Mary Carter of Blood Red Shoes.-Technical information:...
  
  , a seven string guitar with three coursed strings
• Vihuela
  Vihuela
  Vihuela is a name given to two different guitar-like string instruments: one from 15th and 16th century Spain, usually with 12 paired strings, and the other, the Mexican vihuela, from 19th century Mexico with five strings and typically played in Mariachi bands.-History:The vihuela, as it was known...
  
  
• Oud
  Oud
  The oud is a pear-shaped stringed instrument commonly used in North African and Middle Eastern music. The modern oud and the European lute both descend from a common ancestor via diverging paths...
  
  
• Bajo Sexto
  Bajo sexto
  A bajo sexto is a musical instrument with 12 strings in 6 double courses, used in Mexican music. It is used primarily in norteño music of northern Mexico and across the border in the music of south Texas known as "Tex-Mex", "conjunto, or "música mexicana-tejana".A similar instrument with five...
  
  
• Charrango
• Cumbus
  Cümbüs
  The cümbüş is a Turkish stringed instrument of relatively modern origin. Developed in the early 20th century by Zeynelabidin Cümbüş as an oud-like instrument that could be heard as part of a larger ensemble. In construction it resembles both the American banjo and the Middle Eastern oud. A...
  
  

Instruments that use three-string courses include:

• Tiple
  Tiple
  Tiple is the Spanish word for treble or soprano, is often applied to specific instruments, generally to refer to a small chordophone of the guitar family. A tiple player is called a tiplista.-Colombian tiple:...
  
  
• Twelve-string bass
  Twelve-string bass
  The twelve-string bass is an electric bass with four courses each of three strings.Normal tuning is eeE-aaA-ddD-ggG, with one string of each course tuned similarly to the corresponding string of the four-string bass, and the remaining two strings tuned to the octave.-Notable 12-string Bassists:*...
  
  

Mandolins

All members of the mandolin

Mandolin

A mandolin is a musical instrument in the lute family . It descends from the mandore, a soprano member of the lute family. The mandolin soundboard comes in many shapes—but generally round or teardrop-shaped, sometimes with scrolls or other projections. A mandolin may have f-holes, or a single...

 family except the lowest-pitched have courses each of two or three strings, most commonly eight strings in four courses.

The exception, the mando-bass, has four individual strings.

Baroque guitar

The baroque guitar

Baroque guitar

The Baroque guitar is a guitar from the baroque era , an ancestor of the modern classical guitar. The term is also used for modern instruments made in the same style....

 has five courses, with the top four always double strung, and the bass string either double or single.

There are also several patterns of modern ten-string guitar

Ten-string guitar

There are many varieties of ten-string guitar, including:* Both electric and acoustic guitars.* Instruments used principally for classical, folk and popular music.* Both coursed and uncoursed instruments.-Ten-stringed harp guitars:...

 but all have ten single strings, played individually.

Twelve-string guitar

The twelve-string guitar has twelve strings in six courses. The courses are most often tuned E-A-D-G-B-E similarly to a six-string guitar, however older instruments were often tuned one tone lower D-G-C-F-A-D to reduce the tension on the neck, and commonly played with a capo

Capo

A capo is a device used on the neck of a stringed instrument to shorten the playable length of the strings, hence raising the pitch. It is frequently used on guitars, mandolins, and banjos. G.B...

 on fret 2.

The lowest three courses (E-A-D) are normally tuned at octaves, with the primary string uppermost and the octave below it, while the upper two courses (B-E) are tuned to unison. The G course is either unison or at octaves.

On some electric twelve-string guitar

Electric twelve-string guitar

The electric twelve-string guitar is an electric guitar with twelve strings in six courses.Both semi-acoustic and solid-body versions exist.-Makers and models:* Fender Musical Instruments Corporation:** Fender Stratocaster XII....

s, and notably the Rickenbacker 360/12

Rickenbacker 360/12

The Rickenbacker 360/12 is an electric guitar made by the Rickenbacker company; it was among the first electric twelve-string guitars. This instrument is visually similar to the Rickenbacker 360...

, the octave strings are below the primary strings.

Twelve-string bass

The electric twelve-string bass has twelve strings in four triple courses. Basses have also been built with six double courses and other configurations but these are rare.

Alternative tunings

The American Noise

Noise

In common use, the word noise means any unwanted sound. In both analog and digital electronics, noise is random unwanted perturbation to a wanted signal; it is called noise as a generalisation of the acoustic noise heard when listening to a weak radio transmission with significant electrical noise...

 band Sonic Youth

Sonic Youth

Sonic Youth is an American alternative rock band from New York City, formed in 1981. The current lineup consists of Thurston Moore , Kim Gordon , Lee Ranaldo , Steve Shelley , and Mark Ibold .In their early career, Sonic Youth was associated with the No Wave art and music scene in New York City...

 is famous for using alternate tuning

Scordatura

A scordatura , also called cross-tuning, is an alternative tuning used for the open strings of a string instrument, in which the notes indicated in the score would represent the finger position as if played in regular tuning, while the actual pitch is altered...

s on their instruments which are mainly double or triple courses, see Sonic Youth's alternate tunings.