Which term is used to describe a sudden loss of balance or feeling faint?

The term that accurately describes a sudden loss of balance or feeling faint is syncope. Syncope refers specifically to a temporary loss of consciousness and muscle strength, often associated with a significant reduction in blood flow to the brain, which can lead to fainting. It is characterized by a brief period of unresponsiveness, typically resulting from factors like vasodilation, dehydration, or orthostatic hypotension.

Dizziness and vertigo are terms related to sensations of imbalance but do not typically encapsulate the complete loss of consciousness; dizziness describes a general feeling of unsteadiness, while vertigo specifically refers to a false sense of motion or spinning. Nausea, while it may occur alongside feelings of dizziness or balance issues, does not accurately describe fainting or the sudden loss of consciousness associated with syncope. Therefore, in the context of the question, syncope is the term that best matches the description of a sudden loss of balance or feeling faint.