A micrometer (μm) is a unit of length equal to one millionth of a meter (0.000001 m). In cybersecurity, the term may occasionally appear in the context of hardware security, such as describing the physical dimensions of microchips, circuit elements, or traces on printed circuit boards. Understanding micrometer-scale measurements is essential for hardware engineers to prevent physical tampering, side-channel attacks, or unauthorized modifications. While not directly related to software security, the micrometer is crucial in the design and analysis of secure hardware components, where even tiny physical changes can impact device security.