“Software architecture is the set of design decisions which, if made incorrectly, may cause your project to be cancelled.” – Eoin Woods

I lilked this definition


Source: http://www.sei.cmu.edu/architecture/definitions.html

Representational state transfer (REST) is a style of software architecture for distributed hypermedia systems such as the World Wide Web. REST strictly refers to a collection of network architecture principles which outline how resources are defined and addressed.

Wikipidea have a good explanation on REST

URL: http://en.wikipedia.org/wiki/Representational_State_Transfer