webinar ‎(plural webinars). 1  An interactive seminar conducted via the World Wide Web. 2  Usually a live presentation, lecture or workshop that happens in real time, as users participate through chatting, video-chatting, file-sharing, or asking questions with a microphone. An interactive seminar conducted via the World Wide Web. 2  Usually a live presentation, lecture or workshop that happens in real time, as users participate through chatting, video-chatting, file-sharing, or asking questions with a microphone.