Area, tract, region, zone, and belt mean an extent of space especially of ground or surface that is distinguishable from its surroundings in appearance or in certain distinctive features.
Area still carries its original implication of clearly marked bounds, but it may be used with reference to a space defined on a map or chart as well as to one the limits of which are actually visible.
- an oasis is a green or fertile area in a desert
- there are vast uncultivated areas even in the most populous of the states
- two colors—aspen and evergreen, not intermingled but lying in solid areas of light and dark
—Gather
Tract, on the other hand, stresses extent rather than limits; it is therefore preferred to area in designating a space that might otherwise be described as an expanse or is thought of as widespread or far stretching and uniform in character.
- beyond the area of small farms lay larger tracts that were immensely productive
—Anderson - a tract of grass, furze and rushes, stretching away to the western horizon
—Shaw
Tract is often used in an extended sense in reference to anything that has extent or duration.
- wide tracts of life—Day Lewis} <a large tract of unwritten history
—S. Eliot
Region suggests reference to some definite place or locality (as on the earth’s surface, in the atmosphere, or in the human body) distinguished from other localities by certain features or by being subject to a particular condition or influence.
- the upper region of the air
- the Finger Lakes region of central New York State
- what region of the brain is the seat of consciousness?
Zone denotes an area or region that suggests a girdle or an encircling band especially on a map or chart.
- the torrid, arctic, and temperate zones
- parcel post zones
- the pelagic zone of the ocean
In broader use it is often applied to an area that forms a band or strip and is distinctly set off from its environs by some peculiarity of feature.
- the firing zone of a battlefield
- the business zones of a city
- that milky way which nightly as a circling zone thou seest powdered with stars
—Milton
Basically belt is a synonym of zone; distinctively, it implies an area characterized by the presence of some distinguishing natural feature (as a particular flora or mineral).
- the corn belt of the U.S.
- a coal belt} In strict technical usage belt is applied to an area less extensive than a zone.
- a belt of conifers extending into the northern mixed forest zone