An inch is a unit of length commonly used in the United States and other countries that follow the imperial system. 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 books and screens. Inches are divided into smaller units called fractions, such as half an inch or a quarter of an inch. This makes it easier to measure and describe objects with precision. The inch is also used in various fields, including construction, engineering, and textiles, where accurate measurements are essential.