The Piano Deconstructed

Glossary of Terms

A comprehensive list of the terms found on the site.
Click on a term to learn more about it.


Action - complicated system of levers that works to throw the hammer at the string
Agraffe - brass guides that are screwed into the cast-iron frame - the agraffes space and level the strings on the end closest to the keyboard


Baby Grand - a grand piano between four-feet nine-inches and five-feet four-inches in length
Back Check - small leather-covered block affixed to the back of each key which catches the hammer as it rebounds from the string
Backstays - metal rods that brace the pedal support structure
Balancier - see "Repetition Lever"
Bass Leg - supporting leg on the bass (left) end of the keyboard
Bentside - the portion of the rim on the treble (right) side that is curved, giving the grand piano its distinctive shape
Braces - wooden posts that support the interior structure of the piano
Bridge - strip of wood which transmits the vibrations of the strings to the soundboard
Bridge Pin - metal pin driven into the top of the bridge which aligns the string as it crosses the bridge
Bushings - felt lining that cushions the moving parts of the action


Capo d'Astro - a metal bar cast into the frame which presses down on the treble strings as they leave the tuning pins, defining one end of their speaking length
Capstan Screw - metal screw attached to the back of the key that adjusts the height of the action
Case - wooden cabinet that houses the playing mechanism and strung back of the piano
Cast-Iron Frame - the metal plate which the strings are held over, designed to withstand the high tension of the strings
Cheek - curved end point of the rim on both the straight and bent sides
Cheekblock - see "Keyblock"
Clavichord - ancestor of the modern grand piano that was able to gradually change dynamics, but could not produce a loud sound
Concert Grand - nine to twelve foot grand piano built for the concert or performance hall
Cristofori, Bartolomeo - (1655-1732) the inventor of the piano
Cross-Strung - the practice of using two bridges, so that the bass strings pass over the tenor and treble strings
Crown - the slight upward curve of the soundboard that pushes up to resist the downbearing of the strings


Damper - small felt-padded block that rests on the string, stopping it from vibrating
Damper Pedal - the pedal on the right, which raises all of the dampers, allowing the sound to be sustained
Double Escapement - the process which allows action to reset when the key is partially released, so that the hammer can quickly repeat the strike of the string
Drop Screw - small screw that extends from the bottom of the hammer flange which stops the upward motion of the repetition lever
Duplex Scaling - a design which allows portions of the string that are not struck by the hammer to vibrate sympathetically with the section that has been struck


Erard, Sebastien - (1752-1831) inventor of the double escapement action as well as numerous other improvements to the grand piano
Escapement - the process which allows the hammer to disengage from contact with the rest of the action, so that the hammer moves towards the string on its own inertia - double escapement allows the action to reset when the key is partially released, so that the hammer can quickly repeat the strike


Fallboard - see "Keyboard Cover"
Felt - material used to cushion parts of the playing mechanism, and damp the vibrations of portions of the strings
Ferrule - bottom portion of the leg of the piano
Flanges - small hinges in which a moving parts of the playing mechanism rotate
Front Half - portion of the lid that folds over when closed


Grand Piano - piano in which the strings and soundboard are in a horizontal position, distinguished by its wing-shaped case, derived from the shape of the harpsichord


Half Prop - part of the lid prop that is used to keep the lid partially open
Hammer - part of the action which strikes the string with a felt head, causing the strings to vibrate
Harp - see "Cast-Iron Frame"
Harpsichord - an ancestor of the modern grand piano which was capable of producing a loud sound, but could not gradually change dynamics
Hitch Pin - metal pin driven into the cast-iron frame upon which the end of the string opposite the tuning pin terminates



Jack - part of the action that, when lifted by the key, propels the hammer toward the string - a key part of Cristofori's escapement action


Keybed - part of the inner structure of the piano on which the keyframe and keyboard rest
Keyblock - removable wooden blocks that hold the keyboard tightly in place
Keyboard - the 88 keys of the piano and the keyframe which they are mounted upon
Keyboard Cover - moving part of the case that closes to protect the keys
Keyframe - wooden frame on which the keyboard and action rest
Keys - weighted wooden levers which are activate by the pianist - each key controls its own action and damper assembly
Keyslip - long wooden strip that runs the length of the keyboard beneath the keys, and covers the keyframe
Knuckle - leather-covered part found on the bottom of the hammer which is lifted by the jack, causing the hammer to strike the string


Leads - small lead weights inserted into the keys in order to balance the action
Let-Off Button - part of the action that causes the jack to rotate out from beneath the hammer knuckle - a key part of Cristofori's escapement action
Lid - wooden cover that folds down to protect the inside of the piano
Lid Prop - wooden stick that is raised to hold the lid open
Living Room Grand - a six or seven foot grand piano
Lyre - wooden posts which are attached to the bottom of the case and support the pedals
Lyre Box - see "Pedal Box"


Music Desk - part of the case that holds the printed music upright
Music Shelf - bottom portion of the music desk which the base of the music rests upon


Nameboard - part of the case that bears the name of the piano manufacturer - it is usually part of the keyboard cover


Overstrung - see "Cross-Strung"


Parlor Grand - see "Living-Room Grand"
Pedal Box - wooden box that houses the three pedal feet
Pedal Support Structure - part of the case designed to support the pedals
Pedals - there are usually three pedals which can be activated to affect the tone of the piano
Pinblock - block of laminated wood which holds the tuning pins
Plate - see "Cast-Iron Frame"
Point Leg - supporting leg on the end opposite the keyboard



Rails - rails support a common body of parts in the playing mechanism of the piano, such as the keys or dampers
Repetition Lever - a key part of the double escapement action, the repetition lever compresses the repetition spring, which forces the hammer upward when the key is partially released
Repetition Spring - a key part of the double escapement action, the repetition spring is compressed by the repetition lever, and forces the hammer upward when the key is partially released
Ribs - wooden support strips found on the bottom of the soundboard
Rim - curved wooden portion of the casework that gives the grand piano its familiar and distinctive shape
Roller - see "Knuckle"


Sostenuto Pedal - the middle pedal, which acts as a selective damper pedal
Soundboard - the large wooden board that is linked to the strings by the bridges - the vibrations of the strings are transferred to the soundboard, which amplifies the sound.
Spine - the straight portion of the rim found on the bass (left) side of the piano
Spoon - a small metal support affixed to the wippen which supports the jack
Strings - high-tensile steel wires held at high tension across the frame
Stringing - the process of spacing installing the strings across the frame
Sustain Pedal - see "Damper Pedal"


Tail - the part of the rim at the opposite end of the keyboard - it is curved to match the bentside
Treble Leg - the supporting leg on the right (treble) side of the keyboard
Tone Collector - the metal plate that unifies the braces of the back frame into a common vibrating area
Tuning Pin - a pin driven into the pinblock to which one end of the string is attached - the pin can be turned to adjust the pitch of the string


Una Corda Pedal - the left pedal, which shifts the action and keyboard to the right, so that the hammers strike fewer strings


Voicing - adjusting the timbre of the piano by manipulating the felt of the hammer head


Web - holes in the cast-iron frame which allow more sound waves to radiate from the soundboard, and allow access to the pinblock and tuning pins
Wippen - the part of the action that is lifted by the key
Wrest Pin - see "Tuning Pin"
Wrest Plank - see "Pinblock"