What is the origin of the idiom "on edge" and when to use it?

The idiom "on edge" has its origins in the early 17th century. The term "edge" refers to the sharp or thin boundary of a surface, and when used figuratively, it conveys the idea of being in a state of heightened sensitivity or alertness. It is commonly employed in both informal and formal settings to convey a sense of unease or tension. People may use this phrase to describe how they feel before a significant event, such as a job interview, public speaking engagement, or important performance. It is also used to express the general feeling of being on edge due to external factors like stressful situations, uncertain outcomes, or imminent threats.