The common domain extensions are mostly 2 to 3 characters long, but there are more characters than that. The longest one has to be .museum, which is 6 characters long. Here is an APPROXIMATE domain extension names for their uses and your reference:> .com — commercial entities
.org — non-profit organizations
.net -Internet infrastructure and network providers
.edu/.ac — educational institutions
.mil — US military
.gov — reserved for US intergovernmental organizations
.int — international organizations
.biz — business web sites
.name — used by individuals or families for personal use
.info — unrestricted extension for informational websites
.pro — for professional organizations and credentialed professionals
.aero — air-transport industry websites
.museum — for museums
.coop — cooperative associations NOTE: This list does not include .ca .it .tw .cn etc...for other country domain extensions.