I almost forgot to link to the second part of this great piece by Keith Houston on his Shady Characters blog. Part one is here.
Though the origins of the ‘@’ symbol’s visual appearance are murky at best, its use as a shorthand for ‘at the rate of’ is rather better attested. One scholar in particular saw his work reach a far wider audience than might have been expected of an otherwise minor piece of paleographic research: in 2000, a number of newspapers reported on the work of one Giorgio Stabile, an Italian academic who had finally unearthed convincing documentary evidence of the symbol’s meaning, if not its visual appearance.
Stabile’s search for the birth of the ‘@’ started with an analysis of the symbol’s various names. A online survey conducted in 1997 revealed that the symbol went by a multitude of names across 37 different countries, many of them playfully inspired by its shape […]. French and Italian have both ‘proper’ terms — respectively arobase, an archaic unit of weight, and anfora, or ‘amphora’ — and also the more whimsical escargot and chiocciola, both meaning ‘snail’. English uses the cheerlessly direct ‘commercial at’ or, simply, the ‘at sign’.
Stabile observed that despite the symbol’s many metaphorical aliases, only certain names stood out as unrelated to its shape: the English ‘commercial at’, the French arobase (also rendered in Spanish and Portuguese as arroba), and the Italian anfora, or ‘amphora’. ‘Commercial at’ evidently described the character’s typical usage, but arobase/arroba and ‘amphora’ bore further investigation.