Single combat is a duel between two single combatants which takes place in the context of a battle between two armies.
The Kulagysh plate depicting a heroic scene of a single combat that leads to the death of both fighters. Sogdian art from late Sasanian period. Hermitage Museum.
Duel of Peresvet with Chelubei, painting by Viktor Vasnetsov (1914)
A duel is an arranged engagement in combat between two people with matched weapons.
The Code Of Honor—A Duel in the Bois De Boulogne, Near Paris, wood-engraving after Godefroy Durand, Harper's Weekly (January 1875)
Depiction of a judicial combat in the Dresden codex of the Sachsenspiegel (early to mid-14th century), illustrating the provision that the two combatants must "share the sun", i.e. align themselves perpendicular to the sun so that neither has an advantage.
Minamoto no Yoshihira and Taira no Shigemori (Japan in 1159)
Commemorative poster for the fourth centennial of the Disfida di Barletta, the Challenge of Barletta, fought on 13 February 1503 between 13 Italian and 13 French knights all shown wearing full plate armour.