A CDE Definition
The at sign (@), which is shorthand for the word "at," has become widely identified around the world due to its use in Internet email addresses and Twitter names. Officially called an "asperand," the at sign separates the recipient's name from the domain name in email; for example, firstname.lastname@example.org.
A Twitter Symbol
The at sign is a prefix to a member's name on Twitter; for example, @BarackObama is President Obama's Twitter name. See Internet address.
(1) See IP address and Internet domain name.
(2) There are two major types of addresses on the Internet. One is a person's email address, and the other is a website address, which is known as a URL. Following is an explanation of Internet email addresses only. For more on URLs, see URL and Internet domain name.
Email Address Format
The format for addressing a message to an Internet user is USER NAME @ DOMAIN NAME. For example, the address of the author of this database is email@example.com. There are no spaces between any of the words. ALAN is the user name and COMPUTERLANGUAGE.COM is the domain name. The .COM stands for the commercial top-level domain category (see Internet domain name). For the actual structure of an Internet address, see IP address.
Get Your Own
Email addresses are obtained from an Internet service provider (ISP). You can generally choose any name for the first part of the address as long as it is not already taken. The second part is the ISP's domain name. However, if you change your service, your Internet address changes. To obtain a permanent email address, you can register your own domain name or you can use an email service. See how to register a domain name and email interfaces.
Find Someone Else's
There are websites that maintain directories, or white pages, of email addresses. New sites are coming online all the time. You may have to try several sites to find someone, and there is no guarantee. See Web white pages and Web Yellow pages.
Before/After Your Search Term
|AT bus||At Work|
|AT command set||AT&T GIS|
|AT interface||AT&T WorldNet|
|AT keyboard connector||ATA-100|
Terms By Topic
Click any of the following categories for a list of fundamental terms.