What is out-stream video?!?

Seeing the term only once, this digital video tool is super new to me. Hope I am not the only one? From the few sources I found discussing out-stream the meaning of this advertising tool varies. 

According to eMarketer, out-stream video is a form of digital advertising in which video units are served in non-video environments, including text articles, social media feeds and video games. “The term ‘out-stream’ is meant to distinguish these ads from formats that run within a video stream, such as pre-roll, mid-roll and post-roll,” said Paul Verna, principal analyst at eMarketer. 

Below is an example of what an out-stream video ad looks like, via Adform, a global digital media advertising technology company.

Responsive In-View Out-Stream Video Format Demo from Adform on Vimeo.