According to Webinar.nl
The word ‘webinar’ is a blend of ‘web’ and ‘seminar’. A webinar is an event held on the internet which is attended exclusively by an online audience. This distinguishes it from a webcast, which also includes the presence of a physical audience. Other terms used as alternatives for webinar are web event, online seminar, webcast, web lecture and virtual event. Some of most famous general webinar examples are Webmaster Broadcast, Facebook Live, YouTube Live, Instagram Live etc.