Yes MobileMania, many folks "may have his/her own way to define to a layman."
So what is your definition?
Similarly, what is the population to which you will be addressing your definition?
Further, what purpose do you hope to serve?
--- For instance,
--- A technical understanding?
--- A historical / developmental understanding?
--- A social/cultural reflection cast by influence of Internet?
--- A reflection on Internet impact on business and commerce? or upon science/academia/government agencies?
--- An understanding that paces with the emerging hardware that is becoming more popular? (e.g. hardware defining/influencing Internet)
Take a shot.
Perhaps with your own efforts displayed, others may be able to contribute with comparison and contrast.
Without you taking further participation, potential helpers must rely upon broad-based resourcing such as wiki and search engine.