Based on my understanding throughout this semester, Web service is a method of communication between two electronic devices over the World Wide Web. A Web Service is a software function provided at a network address over the web or the cloud, it is a service that is "always on" as in the concept of utility prograamming.
As you can see, the above picture is an example of a web service model. It consists of service registry, provider, and requestor. Service provider is the owner of the service where the ws will be publish inside of the registry. Service registry is where all of the ws resides in. It also contains service descriptions. Whereas, service requestor is the one who wants to use the service as provided by the service provider inside of the service registry.
well then, thank you