It is hard to say, many a times I think web services=web application, it is an application/service that is accessed via web over a network such as the Internet or an intranet. SOA and web services are two different things, but web services are the preferred standards-based way to realize SOA.
SOA is an architectural style for building software applications that use services available in a network such as the web. It promotes loose coupling between software components so that they can be reused. Web Applications in SOA are built based on services. A service is an implementation of a well-defined business functionality, and such services can then be consumed by clients in different applications or business processes.
SOA establishes an architectural model that aims to enhance the efficiency, agility, and productivity of an enterprise by positioning services as the primary means through which solution logic is represented in support of the realization of the strategic goals associated with service-oriented computing.
Web services is the method which is used by different applications in SOA architecture to communicates to each other.
