An electronic book (e-book) is a digital publication that can consist of text, images or a combination of both. An electronic book can be read on a proprietary digital device (an e-reader) or on a computer, which requires special software.
An online lecture is an educational lecture designed to be posted online. Lectures are recorded to video, audio or both, then uploaded and made viewable on a designated site. Students may go to a certain designated site to view the lecture online at a time which is convenient for them.