Etymology is the study of the origin of words and the way their meanings change over time. The sources which are available to us suggest two theories relating to the where Strathardle got its name.
The first theory is explained in Notes on Strathardle (1888):
‘The Gaelic name of the strath is Strath-ardshil, pronounced Sra-ardil, and is supposed to be derived from two Gaelic words meaning the strath of high stream or river – either having reference to the high sources of the river, or to its being more elevated in comparison with another stream, such as Athole – in Gaelic Athshil.’
Therefore, it would seem, the name would have evolved from Strath-Athshil to Strathardle.
The second theory is more plausible and is the one most commonly held. The Rev. Allan Stewart, the parish minister of Kirkmichael in 1790s, wrote about Glenshee and Strathardle’s history in the First Statistical Account of Scotland. His entry for the Parish of Kirkmichael says that:
‘According to tradition, Strathardle was anciently called in Gaelic, Srath na muice brice; the strath of the spotted wild sow; which name it is said to have retained till the time of the Danish invasions, when, in a battle fought between the Danes and the Caledonians, at the head of the country, a chief, named Ard-fhuil, high, or noble blood, was killed, whose grave is shown to this day. From him the country got the name of Srath Ard-fhuil, Strathardle.’
Notes on Strathardle also admits that this is a more likely explanation, stating:
‘It appears that the strath’s original name was, in Gaelic, Strath na muic breac…[i.e.] the strath of the bridled boar; so it seems very probable that the changing of it was in some way connected with the above-named hero [Ardil].’