What is the difference between a webcast and a webinar?

A webinar is usually a smaller, interactive session built around discussion — tens to hundreds of participants who may all be able to speak. A webcast is a one-to-many broadcast built for scale, from hundreds to tens of thousands of viewers, where interaction happens through chat, Q&A, and polling rather than open audio. Enterprise webcasts also carry requirements webinars typically do not: network-aware delivery, single sign-on, and retention of the recording.