Allochiria is the mislocation of sensory stimuli to the corresponding opposite half of the body or space. Obersteiner (1882) introduced the term allochiria (Greek allos = other + chiria = hand), and more than 20 authors employed it in this context over the next 25 years. Stewart (1894) described a related phenomenon in which stimuli are displaced to a different point on the same extremity. He noted that the displacements were different than allochiria and coined the term allachaesthesia (ie, allesthesia) (Greek allaché = elsewhere + aisthésis = perception). Despite this historical background, Jones (1907) redefined both terms in an attempt to increase diagnostic specificity and attributed allochiria to hysteria. Jones' reinterpretation does not appear to be justified historically, etymologically, or scientifically and has resulted in contradictory definitions of allochiria and allesthesia in present-day medical dictionaries and neurologic textbooks. We advocate a return to usage consistent with the original descriptions and word derivations.