Although etymologists agree that the word "tapas" comes from the Spanish word tapar, which means "to cover," that's where agreement on the origin of the Spanish snack-stravaganza ends.
Seminal cookbook The Joy of Cooking claims that "tapas" originally referred to slices of bread or meat used to cover glasses of sherry served in Andalusian taverns. The covers -- especially the salty meat -- served the dual purpose of keeping flies out of the sherry and encouraging patrons' thirst. My handy Food Lover's Companion backs up this theory. Although it's the most popular theory currently in play, there's more to the history of tapas than just sherry.
Places serving tapas-style dishes predate restaurants, and were once one of the only places people could get food outside of their own homes prior to the 18th century. "France was the birthplace of what we now call the restaurant," write Jean-Louis Flandrin and Massimo Montanari in Food: a Culinary History. "With the exception of inns, which were primarily for travelers, and street kitchens...where in Europe at that time could one purchase a meal outside the home? Essentially in places where alcoholic beverages were sold, places equipped to serve simple, inexpensive dishes either cooked on the premises or ordered from a nearby inn or food shop, along with wine, beer, and spirits, which constituted the bulk of their business."
Taverns such as these, Flandrin and Montanari note, "existed not only in France but also in other countries. In Germany, Austria, and Alsace, Brauereien and Weinstuben served delicatessen, sauerkraut, and cheese, for example; in Spain bodegas served tapas."
In keeping with the tavern tradition, a good tapas restaurant should ideally feature an excellent selection of beverages -- especially wine -- and a cozy, relaxing atmosphere. Tapas restaurants aren't fancy; they're familiar. And these days, tapas dishes should be appropriately sized for sharing with friends. The days of a meal fitting on top of your glass are long over.