Disequilibrium is the sensation of being off balance, and is most often characterized by frequent falls in a specific direction. This condition is not often associated with nausea or vomiting.
Unlike dizziness, vertigo has a rotational, spinning component, and is the perception of movement, either of the self or surrounding objects. Disequilibrium simply means unsteadiness, imbalance, or loss of equilibrium that is often accompanied by spatial disorientation.