complete armour, or the whole equipage and accoutrements of a cavalry heavily armed; as caisse, cuirass, &c. The word is formed of the French harnois; which some derive from the Greek agnus, “a lamb’s skin,” because they anciently covered themselves therewith. Du Cange observes, that the word harnesium is used in the corrupt Latin in the same sense, and that it comes from the High Dutch harnas or harnisch. Others derive it from the Italian armi; others from the Celtic harnes, “a cuirass.”

Under King Richard II. it was expressly forbidden all men to ride in harness with lancegays. Vide stat. 7. Richard II. cap. 13. In the statute 2 Hen. VI. cap. 14. Harness seems to include all kinds of furniture for offence as well as defence, both of men and horse; as swords, buckles for belts, girdles, &c.

Harness is also used for the furniture put on a horse to draw in a coach or waggon, or other carriage; such as collars, leathers, traces, &c.