A video that is relatively short in length.  Created for many reasons; for example, by influencers on social media as well as by commercial advertisers, a short-form video is generally no more than 60 seconds.  TikTok is the most well-known social media platform for short videos.  The actual length of a short-form video is arbitrary.  A video less than 10 minutes has been considered short form as well.  See 
TikTok and 
short-form writing.