The clarion (also rest or sufflue) is a rare charge in heraldry of uncertain meaning and purpose. It originates from England and is still largely exclusive to that country, though latterly it has been imported to other Anglophone nations. In Canadian heraldry, it is the cadency mark of a ninth daughter.

It is generally said to represent a kind of wind instrument such as a panpipe or recorder, but does not resemble the trumpet-like clarion known to modern musicians. It may also be intended as an overhead view of a keyboard instrument such as a spinet. Alternatively it has been said to represent a 'rest', a device used by mediaeval knights to support a lance during jousting. In his Display of Heraldry John Guillim suggests that it may be a rudder. 'Clarion' is also the name given to a stop on an organ which imitates the sound of a trumpet.

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  Depiction of a heraldic clarion.
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  Arms of Robert, 1st Earl of Gloucester (1090-1147) in the Tewkesbury Abbey Founder's Book, with three clarions.
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  Coat of arms of American president Chester A. Arthur, based on the Arthur arms of England: Gules a chevron argent between three clarions or.
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  Thomas Grenville arms, Bideford church, Devon