Webcast vs Webinar

What is the difference between a Webinar and a Webcast?

Webcast 
A webcast is a stream of one or more presenter(s) and content where no interaction is permitted from the remote audiences tuning in.

Webinar
A webinar is a stream of one or more presenter(s) and content with a moderate level of remote audience interaction, such as Q&A, polling, or chat functionality.