Such malposition and contact of the maxillary and mandibular teeth as to interfere with the highest efficiency during the excursive movements of the jaw that are essential for mastication. (Jablonski, Illustrated Dictionary of Dentistry, 1982)
Dental occlusion in which the occlusal contact of the teeth on the working side of the jaw is accompanied by the harmonious contact of the teeth on the opposite (balancing) side. (From Jablonski, Dictionary of Dentistry, 1992, p556)