What is the difference between a portal and a web-application?

All portals are web applications, but not every application is a portal. Nearly everything that runs on the internet are web applications. On the other hand, portals are a type of website designed to provide communication and services to the general public. For example a business website is not a portal. You visit a corporate website only when you need information about that company. A dynamic portal updates itself frequently depending on a set of parameters. It can offer so much and attract so many people.