Quite simply put Tapa just means a lid or to cover something. I have been told that many years ago it started in Almería by people putting a saucer on top of their beer to keep the flies out of it. (A very sensible idea as I wouldn’t give a fly any of my beer) Later this developed and somehow food was put on to the saucer, thus the beer had been tapered. Also this was a gesture from the proprietor and enabled clients to stay longer. Tapas were originally free and in Almería and Granada they still are. In other counties you may be lucky to get a few nuts or a couple of olives.