[ noun ] a short sleeveless outer tunic emblazoned with a coat of arms; worn by a knight over his armor or by a herald <noun.artifact>
Tabard \Tab"ard\, n. [OE. tabard, tabart; cf. Sp. & Pg. tabardo, It. tabarro, W. tabar, LGr. ?, LL. tabardum.] A sort of tunic or mantle formerly worn for protection from the weather. When worn over the armor it was commonly emblazoned with the arms of the wearer, and from this the name was given to the garment adopted for heralds. [Spelt also {taberd}.]
In a tabard he [the Plowman] rode upon a mare. --Chaucer.