Tortoiseshell in the context of Tortoise

Inlay covers a range of techniques in sculpture and the decorative arts for inserting pieces of contrasting, often colored materials into depressions in a base object to form ornament or pictures that normally are flush with the matrix. A great range of materials have been used both for the base or matrix and for the inlays inserted into it. Inlay is commonly used in the production of decorative furniture, where pieces of colored wood, precious metals or even diamonds are inserted into the surface of the carcass using various matrices including clear coats and varnishes. Lutherie inlays are frequently used as decoration and marking on musical instruments, particularly the smaller strings.

Perhaps the most famous example of furniture inlay is that of André-Charles Boulle (1642–1732) which is known as Boulle work and evolved in part from inlay produced in Italy during the late 15th century at the studiolo for Federico da Montefeltro in his Ducal Palace at Urbino, in which trompe-l'œil shelving seems to carry books, papers, curios and mathematical instruments, in eye-deceiving perspective. The similar private study made for him at Gubbio is now in the Metropolitan Museum of Art.

Marquetry (also spelled as marqueterie; from the French marqueter, to variegate) is the art and craft of applying pieces of veneer to a structure to form decorative patterns or designs. The technique may be applied to case furniture or even seat furniture, to decorative small objects with smooth, veneerable surfaces or to freestanding pictorial panels appreciated in their own right.

Marquetry differs from the more ancient craft of inlay, or intarsia, in which a solid body of one material is cut out to receive sections of another to form the surface pattern. The word derives from a Middle French word meaning "inlaid work".

The cetera or cetara is a plucked string instrument played in Corsica. It has sixteen, or sometimes eighteen, metal strings, running in paired courses, with a body similar to the mandolin, but larger, and is plucked with a plectrum made of horn or tortoiseshell.

The Italian term also occurs in historical sources and usually interpreted to indicate a musical instrument of the cittern family.

André-Charles Boulle (French pronunciation: [ɑ̃dʁe ʃaʁl bul]; 11 November 1642 – 29 February 1732), le joailler du meuble (the "furniture jeweller"), became the most famous French cabinetmaker and the preeminent artist in the field of marquetry, also known as "inlay". Boulle was "the most remarkable of all French cabinetmakers". Jean-Baptiste Colbert (29 August 1619 – 6 September 1683) recommended him to Louis XIV of France, the "Sun King" (r. 1643–1715), as "the most skilled craftsman in his profession". Over the centuries since his death, his name and that of his family has become associated with the art he perfected, the inlay of tortoiseshell, brass and pewter into ebony. It has become known as Boulle work, and the École Boulle (founded in 1886), a college of fine arts and crafts and applied arts in Paris, continues today to bear testimony to his enduring art, the art of inlay.

Boulle work (also known as buhl work) is a type of rich marquetry process or inlay perfected by the French cabinetmaker André-Charles Boulle (1642–1732). It involves veneering furniture with tortoiseshell inlaid primarily with brass and pewter in elaborate designs, often incorporating arabesques.

Although Boulle did not invent the technique, he was its greatest practitioner and gave his name to it. Boulle came from a well-known Protestant family of artists in France living primarily in Paris but also in Marseille. The first recorded payment to Boulle by the crown, from 1669, specifies ouvrages de peinture, suggesting that he was originally a painter. Boulle was awarded the title of master cabinetmaker around 1666; in 1672 he received the post of Premier ébéniste du Roi and was admitted to a group of skilled artists maintained by Louis XIV, in the Louvre Palace. In 1672 Boulle received a warrant signed by the queen, giving him the added title of bronzier as well as Ebeniste du Roi. One of Boulle's greatest masterpieces is his decoration of the dauphin's private study, created between 1681 and 1683. Boulle's masterpieces are now mostly in museums and have come to represent the wealth, luxury and finesse of the court of Louis XIV, the Sun King.

The zheng (pinyin: zhēng; Wade–Giles: cheng), or guzheng (Chinese: 古筝; pinyin: gǔzhēng; lit. 'ancient zheng'), is a Chinese plucked zither. The modern guzheng commonly has 21, 25, or 26 strings, is 64 inches (1.6 m; 5 ft 4 in) long, and is tuned in a major pentatonic scale. It has a large, resonant soundboard made from Paulownia wood. Other components are often made from other woods for structural or decorative reasons. Guzheng players often wear a fingerpick made from materials such as plastic, resin, tortoiseshell, or ivory on one or both hands.

It can have nylon steel strings, steel strings, silk strings, etc., depending on the genre. The most common guzheng has 21 strings. The high-pitched strings of the guzheng are close to the player, and the low-pitched strings are on the opposite side. The strings' order from the inside to the outside is 1 to 21.