Desculpem o texto em inglês, mas não resisti. Todos os dias recebo uma palavra do yourDictionary.com na minha mailbox. A escolha é sempre apropriada, engraçada, bem explicada; as palavras são sempre ótimas e inesperadas. A de hoje, aliás, sequer é uma palavra.
Definition 1: The "at" sign, used to mark the value or cost per item or to separate the user name from the domain name in an e-mail address.
Usage 1: For most of its history in the United States, the "at" sign has been used to refer to prices: "Today's Special—5 lb. potatoes @ $1 a lb." It's a humble job, but one that needs doing. With the advent of the technological economy, the @ sign lends its appropriate coded meaning to e-mail addresses the world over.
Suggested usage: Linguists have compiled a list of names for the ubiquitous @ sign. European languages associate @ with animals. In Dutch, it's called apestaart "monkey's tail." In Finnish it's either kissanhäntä "a cat's tail" or miau merkki, transliterated "meow merk-key," a second-stage development of the @ sign's resemblance to a cat. Germans call @ a Klammeraffe "spider monkey" (literally, "clinging monkey"), and in Serbian, the word is majmun "monkey." To the Russians, the @ looks like the curled tail of a dog, hence their name sobachka "little dog." Some Swedes call it "Snabel-A" or "elephant-trunk A" while others prefer the culinary term, kanelbulle "cinnamon bun." In Hebrew opinion is again split between an animal and food: the sign in Hebrew is either ashablool "snail" or strudel. In French, the story is much less picturesque. The @ is called a "business a," which relates to its etymology (for which see below).
Etymology: In 1972, the programmer Ray Tomlinson was working on a network addressing system that would clearly separate the username from the machine and domain identities. Tomlinson chose the @ because its widely known meaning fit its use and because never appears in a proper name. But the @ had been around a long time before the computer revolution. The @ in English probably originated with the French à in expressions like: ten apples a Euro = dix pommes à Euro. We may also have inherited it from Spanish or Portuguese, who used a similar sign for their "arroba" from the Arabic ar-roub "the quarter," a measure of solids and liquids. The evidence for either story is sketchy. (Thanks to the curiosity of Don J. DeBenedictis for raising questions about today's non-Word of the Day.)
—Audra Himes, yourDictionary.com