A zone of a sphere is the part between two parallel planes. If the sphere has radius r and the distance between the planes is h, the area of the curved surface of the zone equals 2πrh.
A circumscribing cylinder of a sphere is a right-circular cylinder with the same radius as the sphere and with its axis passing through the centre of the sphere. Take the circumscribing cylinder with its axis perpendicular to a zone’s bounding planes, as shown. It is an interesting fact that the area of the curved surface of the zone is equal to the area of the part of the circumscribing cylinder between the same two planes.
in a network. Informal A subnetwork within a larger network. See domain.
The area of the Internet administered by a particular name server which forms part of the Internet Domain Name Service. Details of the zone are stored in a file known as the zone file.
1. (biostratigraphic zone) A unit of rock characterized by a clearly defined fossil content. To avoid confusion with other types of zone the term ‘biozone’ (short for ‘biostratigraphic zone’) is preferred by many authorities, although the term ‘biozone’ is also used in a different sense. The term is usually qualified to denote the type of zone. See acme zone; assemblage zone; concurrent range zone; lineage zone; oppel zone; range zone; subzone; taxon range zone; teilzone; zonule; index fossil.
2. In crystallography, a set of crystal faces whose intersecting edges are parallel. They are also parallel to, and may be rotated about, a zone axis. See crystal zoning.
3. See metamorphic zone.
- ethyl iodide
- ethyne
- ETI
- e-ticket
- etiolation
- ETR
- Etruscans
- Ettinghausen effect
- ETX/ACK
- E-type asteroid
- eu-
- Eubacteria
- Eubilides
- eucarpic
- Eucaryota
- eucaryote
- euchromatin
- Euclid
- Euclid (300)
- Euclid (300 bc)
- Euclid (330?–275? bc)
- Euclidean Algorithm
- Euclidean construction
- Euclidean distance
- Euclidean domain