A brief glimpse refers to a very short, fleeting moment in which one gets to see or experience something. It is an instantaneous view or insight into something that lasts only for a few seconds before it disappears again. The term can be used in various contexts such as seeing someone briefly while passing by, catching a glimpse of something out of the corner of your eye, getting a brief understanding of a situation, etc. Essentially, it is an opportunity to experience or witness something for just a moment before it's gone again.