.com (commercial) is a generic top-level domain (gTLD) used on the Internet's Domain Name System. It was one of the original top-level domains (TLDs), established in January 1985, and has grown to be the largest TLD in use. It was originally administered by the United States Department of Defense.
Although .com domains are officially intended to designate commercial entities (others such as government agencies or educational institutions have different top-level domains assigned to them), there has been no restriction on who can register .com domains since the mid-1990s. The opening of the .com registry to the public coincided with the commercialization and popularization of the Internet, and .com quickly became the most common top-level domain for websites. Many companies which flourished in the period between 1997-2001 (the time known as the "dot-com bubble") went so far as to incorporate .com into the company name; these became known as dot-coms or dot-com companies.