An inch is a unit of length in the imperial system, commonly used in the United States and the United Kingdom. It is defined as exactly 2.54 centimeters. The inch is often used to measure small distances, such as the height of a person or the dimensions of objects like a smartphone or a piece of paper. Inches are divided into smaller units called fractions of an inch, such as half an inch or a quarter of an inch. This makes it easier to measure and describe objects with precision. Tools like rulers and tape measures typically display measurements in inches, making them essential for various tasks in construction and crafting.