Definition of the word size up

The phrase "size up" is an idiomatic expression that refers to the process of making a quick assessment or judgment about a situation, person, or object. The root of this expression can be traced back to the late 19th century in the United States, where it was used in the building and construction industry. In the context of building, “to size up” meant to measure the dimensions of a structure, usually with a measuring tape called a "size-up." Carpenters and builders used this expression to suggest that they could accurately "measure up" the dimensions of the space they were building in order to determine how much material they would need to complete the job. Over time, the usage of "size up" expanded beyond the construction industry. It became a figure of speech that conveyed the idea of quickly examining a situation in order to determine its potential risks, hazards, or opportunities. Nowadays, in addition to the construction industry, "size up" is commonly used in various fields such as law enforcement, military, emergency services, and business. In these contexts, the expression still carries its original meaning of making a quick and accurate assessment or evaluation. In summary, the origin of the expression "size up" can be traced back to its use in the building industry to describe measuring a structure's dimensions, and it's still used today in various fields to indicate quickly evaluating a situation or person to determine its essential features.