If fluid enters the lungs or airway instead of being swallowed normally, the medical term is aspiration.
Aspiration occurs when liquid, food, saliva, stomach contents, or another substance passes through the vocal cords into the trachea and respiratory system. It can happen during swallowing, choking, vomiting, impaired consciousness, or conditions that weaken the normal swallowing reflex. A person may cough immediately, although “silent aspiration” can occur without obvious choking.
Aspiration is different from aspiration pneumonia. Aspiration describes the entry of material into the airway or lungs; aspiration pneumonia is an infection that can develop afterward, especially when bacteria-containing material reaches the lower respiratory tract. Inhaling sterile stomach acid can instead cause chemical inflammation called aspiration pneumonitis. The word aspiration can also refer to a medical procedure in which fluid or tissue is removed with suction or a needle, so context matters. In the question’s context, however, it means accidental inhalation of fluid into the respiratory tract.