A baldachin, or baldaquin (from Italian: baldacchino), is a canopy of state over an altar or throne. It had its beginnings as a cloth canopy, but in other cases it is a sturdy, permanent architectural feature, particularly over high altars in cathedrals, where such a structure is more correctly called a ciborium when it is sufficiently architectural in form. A cloth of honour is a simpler cloth hanging vertically behind the throne, which may be combined with a canopy.

"Baldachin" was originally a luxurious type of cloth from Bagdad, from which name the word is derived, in English as "baudekin" and other spellings. Matthew Paris records that Henry III of England wore a robe "de preciosissimo baldekino" at a ceremony at Westminster Abbey in 1247. The word for the cloth became the word for the ceremonial canopies made from the cloth.

In the Middle Ages, a hieratic canopy of state or cloth of state was hung over the seat of a personage of sufficient standing, as a symbol of authority. The seat under such a canopy of state would normally be raised on a dais. Emperors and kings, reigning dukes and bishops were accorded this honour. In a 15th-century manuscript illumination the sovereign Grand Master of the Knights Hospitaller in Rhodes sits in state to receive a presentation copy of the author's book. His seat is raised on a carpet-covered dais and backed with a richly embroidered dosser (French, "dos"). Under his feet is a cushion, such as protected the feet of the King of France when he presided at a lit de justice. The King of France was also covered by a mobile canopy during his Coronation, held up on poles by several Peers of France.