Last week I went to an event described as a ‘gala concert’ at Bangor University. A friend asked what gala actually means; I wasn’t sure, so decided to find out.
According to the OED, gala (/ˈgaːlə/, /ˈgeɪlə/) means “gala dress, festal attire”; “a festive occasion; a festival characterized by the display of finery and show” or “festive, gay” (chiefly North America). It comes from the French word gala (official reception).
According to the Online Etymology Dictionary, gala comes from the French en gala, which perhaps comes from the Old French gale (merriment), from galer (rejoice, make merry).