The zone lying between the Boreal and Sonoran zones of North America. It includes an eastern or humid subdivision and a western arid one of corresponding temperature comprising the northern Great Plains and the lower slopes of the mountains of the western United States and Mexico. Called also Neutral zone. [Webster 1913 Suppl.]

abyssal zone, antarctic zone, arctic zone, bathyal zone, benthonic zone, canal zone, climatic zone, combat zone, comfort zone, danger zone, demilitarized zone, drop zone, dropping zone, enterprise zone, erogenous zone, free zone, frigid zone, geographical zone, kill zone, killing zone, language zone, littoral zone, loading zone, neritic zone, no-parking zone, north frigid zone, north temperate zone, panama canal zone, parking zone, phase transition, polar zone, safety zone, south frigid zone, south temperate zone, strike zone, temperate zone, tidal zone, time zone, torrid zone, transit zone, transition, tropical zone, twilight zone, war zone, zone, zone fire, zone of interior