What condition refers to an absence of breathing?

The term that refers to an absence of breathing is "apnea." This is a medical condition in which there is a temporary cessation of breath. Apnea can occur for various reasons, including but not limited to sleep disorders, respiratory conditions, or in response to specific stimuli, such as during certain types of anesthesia.

In contrast, the other terms denote different breathing conditions. Dyspnea refers to difficult or labored breathing, often experienced as shortness of breath. Hyperpnea is characterized by an increased depth and rate of breathing, which can happen during intense exercise or in response to metabolic needs. Tachypnea describes an increased respiratory rate, typically exceeding the normal rate, which can indicate distress or a respiratory illness. Understanding these differences is crucial for recognizing various respiratory conditions and their implications in clinical practice.