Normal mode refers to a state in which a system operates under standard conditions, without any external disturbances or alterations. In this state, the system behaves predictably, allowing for consistent measurements and observations. This concept is often used in various fields, including physics, engineering, and computer science, to establish a baseline for performance. In the context of vibrational analysis, normal modes describe the specific patterns of motion that occur when a system, such as a molecule or structure, oscillates. Each normal mode corresponds to a particular frequency and shape of vibration, helping scientists understand the dynamic behavior of the system.