Definition of the word flatten out

The phrase "flatten out" describes the action of making something that is three-dimensional or curved appear flat or two-dimensional. It is derived from two separate words, "flatten" and "out". The word "flatten" comes from the Old English word "flætan", which meant to make something smooth and plane by removing any curves or rough surfaces. This usage of the verb can be traced back to the 13th century. The prefix "out" in "flatten out" indicates a change in state from curved or rounded to flat or spread out. This prefix is an Old English word that was likely taken from Celtic and Germanic languages and was commonly used in Old English to indicate movement away from something. In this case, it's applied to "flatten" to mean "to flatten out". Overall, the meaning of the phrase "flatten out" has evolved over time as new innovations and technologies have emerged, such as the design of buildings and computer graphics. Today, it is often used to describe a specific design or engineering process, such as flattening out a 3D image to make it more easily viewable on a computer screen, or flattening out the ground around a building to make it more stable and even.