What is meant by "cabin depressurization"?

Cabin depressurization refers specifically to a loss of cabin pressure. This situation can arise due to various factors, such as structural failures, breaches in the aircraft's fuselage, or issues with the cabin pressurization system. When depressurization occurs, the external atmospheric pressure, which is significantly lower than that at sea level, begins to equalize with the compartment's pressure, potentially leading to hazardous conditions for passengers and crew.

Understanding this concept is crucial for flight safety, as aircraft are designed to operate at high altitudes where the air pressure is insufficient for safe breathing without supplemental oxygen. Therefore, maintaining cabin pressure is vital for passenger comfort and survival. The other options relate to different aspects of cabin environment but do not describe the condition of cabin depressurization, which is distinctly about pressure loss rather than humidity, temperature, or noise levels.