G5 is the grouping of emerging economies comprising Brazil, China, India, Mexico and South Africa.
G7, the group of the world's most wealthy and industrialized countries founded in 1975, is now better known as G8 after it included the Russian Federation a few years ago.
G8's membership comprises the main industrialised countries. It is not an international organisation, nor does it have an administrative staff with a permanent secretariat. It is a process that culminates in an annual summit at which the heads of state and government of the member countries hold talks with a view to finding solutions to the main world issues.
G14 is the grouping comprising G8, G5 and Egypt. The joint declaration of the G8-G5 summit was actually that of the G14.
G20 is a group of developed and developing countries and is considered a broader international platform. Itwas founded in 1999 with the aim of studying, reviewing, and promoting high-level discussion of policy issues pertaining to the promotion of international financial stability. It seeks to address issues that go beyond the responsibilities of any one organization.
Src: http://ibnlive.in.com/news/what-do-g5-g8-g14-g20-stand-for/96840-2.html
