ptarmigan: [16] Ptarmigan was borrowed from Scottish Gaelic tarmachan, a diminutive form of tarmach ‘ptarmigan’. There is no etymological justification for the spelling pt-. It was foisted on the word in the late 17th century in the erroneous belief that it had some connection with Greek pterón ‘wing’ (source of English pterodactyl).
bird of the grouse family, 1590s, from Gaelic tarmachan, of unknown origin. The pt- spelling (1680s) is a mistaken Greek construction (perhaps based on pteron "wing").
