SOA is a collection of services that are important for developing web applications. The core advantage offered by Service Oriented Architecture is the flexibility it provides to businesses in terms of integrating IT and business processes.
Service Oriented Architecture is very closely related with software engineering. In simple terms SOA is a collection of services that are essential for the development of loosely coupled distributed applications. SOA offers a way for consumers of services, such as web-based applications, to be aware of available SOA-based services.