Nosocomial infections are best described as:

Nosocomial infections are defined as infections that patients acquire while receiving treatment for medical or surgical conditions in a healthcare setting, typically in hospitals. These infections can occur in various areas of healthcare facilities, such as patient rooms, operating rooms, or intensive care units and can be caused by bacteria, viruses, fungi, or parasites.

This definition is crucial as it highlights the specific context in which these infections arise, distinguishing them from infections acquired in other environments or situations. For instance, infections acquired in public places, in clinical trials, or through contaminated food fall outside the typical scope of what constitutes a nosocomial infection. This clarity helps healthcare professionals to implement appropriate infection control measures to reduce the risk of such infections in facilities, ultimately improving patient outcomes.