Service-Oriented Architecture Definition

Agree there are zillion definitions of what SOA is. For some its a technology, product for some, for many its just Web Services and for many more its SO AH !! So here is my definition of a SOA.

“Service-Oriented Architecture is an architecture paradigm or approach to building coarse grained, loosely coupled and reusable services, which perform a well defined business functionality and provides well defined interfaces for invocation by external entities”

I get cannot get simpler than this. So the term services itself warrants a seperate post and what it actually means. But let me take a stab at it. To me a service is a coarse grained function that a provider has built and performs a well defined business operation (eg: Weather Forecast, Car VIN Check etc). This service is consumed or used by a consumer and finally there is a contract using which the service is formally defined by the provider and there also exists a binding SLA between the provider and consumer.