Webcast and webinar are both methods of communicating over the web to many people at one time. The words are formed by combining “web” with broadcast (webcast) and seminar (webinar). These usually involve audio and video streamed over the internet to multiple people at one time.
A webinar is basically an online seminar. It could be a one to many, or a many to many event. The organisers of the webinar are often referred to as the presenters. Alternatively, these could be guest presenters for the organisers, but usually there is a featured speaker and some sort of host. Even though audio is supported, most webinars mute attendees by default to avoid any interference with the presenter’s audio.
A key feature of webinars is they allow for some kind of online interaction between the presenters and the attendees of the online event. These can be simple chat windows where people can type in their comments and questions. Some webinar platforms provide action buttons where presenters can ask attendees to click in order to show agreement. This is basically the same as asking for a show of hands at an in-person seminar. There are sometimes buttons to click if you have a question and the host will call on you and unmute your audio line so you can speak your question.
These features are different from a webcast. Since it is based on a broadcast, you can think of it more like a TV show or news clip. There usually is a single source transmitting content out to many people. It’s a one-way communication only. They can be live or on demand.
For example, many webcasts are just regular broadcast programming simulcast on the web. Viewers can watch it live online. Sometimes the programming can be viewed later too. Another use for webcasts are university lectures for distance learning at universities.