|Sources||Bail-chloichiridh; petsh-ch.: Diack
Baile a’ Chloichridh: East Perthshire Gaelic
Baile' Chloichridh: Robertson
Baile-Chloichridh: 1875 Am Feillire
Baile-chloichridh: Prose Writings of Donald Lamont 65 and 153
The latter part of Pitlochrie - cloichridh means stony place from clach a stone with the suffix ridh of collective force like the ry at the end of the English word cavalry and others, and the whole name means “Portion or Division of the stony place.”Robertson MS381 p. 17
Some years ago I asked an intelligent Gaelic speaking native of the place the origin of the word [Pitlochry], and he said “Oh, that's easily done.” There is a big stone below the town called “Clach a chruidh” where in the old days the Highland drivers rested their cattle on their way to the Falkirk tryst...: Letter to the Scotsman , October 22 1934
Given the local pronunciation of baile as bail, and the meaning which Robertson proposes, it seems that the underlying form here is Baile a' Chloichridh.