There are actually several words (possibly as many as 100 that I am aware of) in English which have Gaelic etymologies. "Smashing", meaning "that's good", "teaming" as in with rain, are two examples which immediately leap to mind.

Ralph Carr, in the proceedings of the Scottish Antiquarian Society (1864-66), ventured the opinion that the pre-Norse inhabitants of Orkney spoke a language akin to Erse. He based his etymology of Maeshowe on this assumption. However, most evidence from what sources there are tend to suggest that the Pictish language was actually down the other trouser leg of Celtic language - being related more to Cumbirc, Welsh & Breton than Gaelic. There is evidence that Orkney was either a Pictish kingdom in it's own right, or was subservant to mainland Picts - there's no evidence that early Orcadians were culturally or linguistically seperated from their mainland contemporaries. If the etymology of the "maes" element is pre-Norse, which I now dispute anyway, then it's likely not to have been in any way related to Gaelic.