webinar
Do you know what a 'portmanteau' is? It is a new word formed by the combination of two or more words. Few examples are: Bluetooth, Blackboard, TeamViewer, Skype, etc.
Here, 'webinar' is even a similar word. It is a recently coined word that is a combination of the words 'web' and 'seminar'.
It is a seminar, lecture, or a paper presentation that takes place through the Internet or what can be called as 'web'.
It is a two-way process that has an advantage of discussion and scope for improvement as well as building of healthy relationship between the presenter and the audience.
Hope this explanation helped you!