Internet gTLD - Generic Top Level Domains

Internet Generic Top-Level Domain (gTLD) extensions used in URL

.aero	Air-Transport industry URL extension sponsored by Societe Internationale de Telecommunications Aeronautique (SITA)
.arpa	Address and Routing Parameter Area URL extension for Internet-infrastructure purposes, controlled by Internet Architecture Board
.biz	Business related URL extension (operated by GoDaddy)
.com	Commercial URL extension (operated by Verisign)
.coop	Co-operative business URL extension (operated by Midcounties Co-operative)
.edu	Education institution URL extension accredited by US Dept. of Education and registered through Educause
.gov	Government URL extension for US Government and operated by General Services Administration
.info	Information Domain URL extension operated by Afilias
.int	Intergovernmental Domain URL extension of organizations established by International treaties between Government operated by IANA .int Domain
.jobs	Jobs URL extension for Human Resource (HR) management operated by GoDaddy
.mil	US Military Domain URL controlled by US DoD Network Information Center
.mobi	Mobile products and services Domain URL extension operated by Afilias
.museum	Museum Domain URL extension operated by International Council of Museums
.name	Name Domain URL extension operated by Name Domain and Verisign
.net	Network Domain URL extension (operated by Verisign)
.org	Organization Domain URL extension (operated by Public Interest Registry)
.pro	Professional Domain URL extension operated by Afilias
.travel	Travel related Domain URL extension operated by Donutsinc/ Travel Domains

Reference information and URL:
1. Country Code Top Level Domain - ccTLD
2. Internet - History and Architecture
3. Domain Name System - DNS