Action
The height of the strings above the fretboard or fingerboard. Higher action generally takes more finger pressure to play but can reduce buzzing; lower action is easier to press but may buzz if set too low.
Bout
The curved outer edge of an instrument’s body. "Upper bout" and "lower bout" describe the regions above and below the waist on guitar- and violin-family bodies.
Bow
A tensioned stick strung with hair (traditionally horsehair) that is drawn across a string to set it vibrating continuously, used on instruments such as the violin, cello, and erhu.
Bracing
An internal lattice of thin wooden strips glued beneath an instrument’s soundboard that reinforces it against string tension while still allowing it to vibrate freely.
Bridge
A raised piece that holds the strings away from the body at the correct height and transmits their vibration into the soundboard or body.
Course
A set of two or more strings tuned closely together (often in unison or an octave apart) and played as a single unit, as on the mandolin or twelve-string guitar.
Fret
A raised strip, usually metal, set across a fretted instrument’s neck that marks exact pitches and lets a player stop a string cleanly at a specific note.
Harmonic
A ringing, flute-like overtone produced by lightly touching a string at a specific point rather than pressing it fully down, isolating one of the string’s natural overtones.
Luthier
A craftsperson who builds or repairs string instruments, historically associated with lutes and guitars but now used broadly across the string instrument family.
Nut
A small ridged piece at the top of the neck, near the headstock, that sets the spacing and height of the strings where they leave the fretboard.
Pickup
A device, usually magnetic or piezo-electric, that converts a string’s vibration into an electrical signal that can be amplified, used on electric and electro-acoustic instruments.
Pizzicato
A technique of plucking the strings of a normally bowed instrument, such as a violin or double bass, with the fingers instead of using the bow.
Plectrum
A small pick, held in the hand, used to pluck or strum a string instrument’s strings; often made of plastic, though other materials are used across traditions.
Resonance
The tendency of an instrument’s body, or of unplayed strings, to vibrate sympathetically in response to a played note, amplifying or coloring its sound.
Reentrant tuning
A tuning in which the strings are not arranged strictly from lowest to highest pitch, as on a standard ukulele, where the top string sits higher in pitch than the one below it.
Saddle
The part of the bridge that the strings rest directly on, which sets their height and, on many instruments, their precise length for intonation.
Scale length
The vibrating length of a string, measured from the nut to the bridge, which influences string tension, feel, and tone at a given tuning.
Soundboard
The thin, resonant top surface of an acoustic instrument’s body, responsible for most of its unamplified volume and tonal character.
Soundhole
An opening cut into an instrument’s soundboard that allows air inside the body to vibrate and project sound outward, as on an acoustic guitar or mandolin.
Sympathetic strings
Strings that are not directly played but vibrate in response to the vibration of other strings or the body, adding resonance, as on the sitar.
Tremolo
A rapid, repeated picking or bowing motion used to sustain a note beyond its natural decay, common on the mandolin and in some bowed-string techniques.
Tuning peg
A mechanism, geared or friction-based, that a player turns to adjust a string’s tension and therefore its pitch.
Vibrato
A controlled, slight oscillation in pitch applied to a sustained note, used expressively across bowed, plucked, and fretted string instruments alike.