1774, "of or pertaining to the Gaels" (meaning originally in English the Scottish Highlanders); 1775 as a noun, "language of the Celts of the Scottish Highlands;" earlier Gathelik (1590s), from Gael (Scottish Gaidheal; see Gael) + -ic.
Gadhelic
gadolinium
gadzooks
Gaea
Gael
Gaelic
gaff
gaffe
gaffer
gag
gaga