a quick look
"I caught just a glimpse of her face before she turned away."
A brief look, glance, or peek.
"As I turned away from the stage, I caught a fleeting glimpse of the actor waving goodbye through the curtain gap."
In plain English: A glimpse is a very short look at something that you can't see clearly for long.
"The quick glimpse through the window showed that her car was gone."
To see or view briefly or incompletely.
"The crowd parted just long enough to give me a glimpse of the hidden garden behind the mansion."
In plain English: To glimpse something means to catch only a quick, brief look at it before you can't see it anymore.
"I caught just a glimpse of her face when she walked past me in the hallway."
The word glimpse comes from Middle English glimsen, which originally meant to dazzle or glisten before evolving into its current sense of catching a quick look. It shares roots with the related word glimmer and ultimately traces back to an ancient Indo-European term for shining.