In heraldry, a fess is a charge on a coat of arms that takes the form of a band running horizontally and centrally across the shield. Writers disagree in how much of the shield's surface is to be covered by the fess, ranging from one-fifth to one-third. A fess is likely to be shown narrower if it is uncharged, that is, if it does not have other charges placed on it, and/or if it is to be shown with charges above and below it; and shown wider if charged.
A fess when couped ("cut off" at either end, and so not reaching the sides of the shield) can be called humetty, but this term is very rare in the Anglophone heraldries and is most often used of the cross.
A fess coticed (also spelt with two ts and/or an s) is closely contained between two narrow strips (cotises), one above and one below. A very unusual exception are the arms of Joseph Frederick Laevens, with a fess cotised on the lower edge.
Though the bar is sometimes termed a diminutive of the fess, this is not necessarily true, as the bar may be no narrower than the fess. In the heraldries of the British Isles two fesses are not usually specified to appear on a shield together, the two fess-like charges being then termed bars. Narrower versions of the bar are called barrulets (little bars). The arms of Baroness Fritchie provide an example of three Barrulets fracted and there conjoined to a Chevronel.
A shield party per fess or just per fess is divided into two parts by a single line which runs in the direction of a fess.
A charge placed horizontally is blazoned fesswise or fessways. Two or more charges arranged in a horizontal row are blazoned in fess or in bar.