(geology) A deep level seismic zone on the line of subduction. This zone can be as deep as 700km.

plural of time zone

The photic zone

(climbing) Land at sufficiently high altitudes that there is not enough oxygen to sustain human life.

(physics) The stage in the flow or a fluid during which it changes from laminar to turbulent / (geology) The region between the upper and lower mantle characterized by a rapid increase in density

plural of seismogenic zone

plural of twilight zone

Third-person singular simple present indicative form of twilight zone

plural of zone defense

A region or context located in between others and therefore not subject to their norms. / (geography) A deteriorating area surrounding a central business district.