A name of uncertain origin, according to Black, but probably from the lands of the same name in Strathearn. The name of the parish of Abernethy refers to a former Pictish royal residence, and an early Christian settlement in the reign of Nethan or Nectan, around 600. Orme, Abbot of Abernethy, granted part of the tithes of the abbey lands to the new abbey at Arbroath. Sir William de Abernethy was implicated in the murder of Duncan, Earl of Fife in 1288 and was condemned to die in prison. However, the fortunes of the family did not suffer greatly, and William de Abernethy, called Lord Saltoun, affixed his seal to the Declaration of Arbroath in 1320. David II added to the family holdings the lands of Rothiemay. Margaret, heiress of the last Abernethy Lord Saltoun, married Sir Alexander Fraser of Philorth whose son was declared by Parliament in 1669 to be Lord Saltoun.
The arms of Abernethy are now to be found quartered with those of Fraser in the achievement of the present chief of that name, Lady Saltoun. Nisbet gives the principal cadet to be Abernethy of Auchnacloich, who used the arms of Abernethy differenced by a bordure. The name of Abernethy also lives on in the styles and titles of the Duke of Hamilton, whose ancestor, the first Marquess of Douglas, was additionally created Lord Abernethy in 1633. John Abernethy, a distinguished physician, is credited with assisting in the discovery of fulminate of mercury which, as an explosive, contributed to the development of modern handguns.