Definition of blank out

The origin of the phrase "blank out" refers to the literal meaning of the word "blank" which originally meant "white" or "undefiled" in Old English. The term "blank paper" was used to describe a fresh, unmarked sheet of paper. In the early 20th century, the term "blank out" began to be used figuratively to describe the act of erasing or deleting something completely, causing it to be forgotten or removed from memory. This phrase was likely inspired by the image of mentally erasing or forgetting something, as if it had been written on the mind's "blank paper". The first known usage of "blank out" in this sense can be found in a 1925 issue of Popular Mechanics magazine, where it was used to describe the phenomenon of forgetfulness or memory loss due to shock or trauma. Today, the term "blank out" is commonly used in everyday speech to describe the act of forgetting, forgetting something temporarily, or causing someone else to forget something through distraction or concentration-breaking activities.