at sign (@)
Definition - The phonogram for the word at.

1. It was originally called the commercial at because it was sometimes used to represent the phrase at the rate of in accounting and commerce.

Etymology -
Ray Tomlinson, a programmer, is credited with starting its use in e-mail addresses. In 1971-72 he implemented the first email system that was able to send mail between users who were on different computers on a network. To be able to specify exact locations on the network, he needed a way to indicate which machine the user was on. To do this he used the @ sign followed by the machine name (e.g. dave@computer1).

Oxford English Dictionary -
The first citation for the symbol's email use is from 1972:
"Others currently involved with FTP include Arvola Chan (AC@MIT-DMCG),+Greg Hicks (HICKS@UTAH) [etc.].]"
(A. Bhushan Request for Comments (Electronic text) No. 414. 1 )

Quotation -
"Some names for the symbol in other languages are:
(1) Snabel, elephant's trunk (Danish)
(2) Klammeraffe, hanging monkey (German)
(3) papaki, little duck (Greek)
(4) kukac, worm (Hungarian)."
(Source: American Headway 4B [an ESL textbook])

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