Like many names beginning with Pit- in Scotland, the English form derives from an older form than the Gaelic. The original Gaelic form was Peit Chloichridh ‘the stead of the stoney place’; this is the form from which the English version derives.
In recent times however, Gaelic dropped the word peit in place-names and in general speech in favour of baile ‘farm’. Peit was originally borrowed from Pictish, but for some reason many loan words from that language are no longer present in Gaelic. That said, there is a Pitlochrie in Glen Isla which is on record as Peit Chloichridh in Gaelic.
Cloichridh is derived from Gaelic clach ‘stone’. A letter to this newspaper in 1934 says there was a big stone below Pitlochry called Clach a’ Chruidh ‘the stone of the cattle’ where Highland drovers rested their cattle on their way to the Falkirk Tryst.
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