noun

• (geography, now rare) Each of the five regions of the earth's surface into which it was divided by climatic differences, namely the torrid zone (between the tropics), two temperate zones (between the tropics and the polar circles), and two frigid zones (within the polar circles).
  "And as two Zones doe cut the Heaven upon the righter side, / And other twaine upon the left likewise the same devide, / The middle in outragious heat exceeding all the rest: / Even so likewise through great foresight to God it seemed best, / The earth encluded in the same should so devided bee […]."
• (by extension) A restricted category or virtual place.
  "The discussion was veering off into a danger zone."
• (crystallography) A series of planes having mutually parallel intersections.
• (baseball, informal) The strike zone.
  "That pitch was low and away, just outside the zone."

verb

• (transitive) To divide into or assign to sections or areas.
  "Please zone off our staging area, a section for each group."
• (transitive) To define the property use classification of (an area).
  "This area was zoned for industrial use."
• (intransitive, slang) To enter a daydream state temporarily, for instance as a result of boredom, fatigue, or intoxication; to doze off.
  "I must have zoned while he was giving us the directions."