delta

(redirected from deltaic)
Also found in: Dictionary, Thesaurus, Medical, Financial, Wikipedia.

delta

1. the fourth letter in the Greek alphabet (Δ or δ), a consonant transliterated as d
2. the flat alluvial area at the mouth of some rivers where the mainstream splits up into several distributaries
3. Maths a finite increment in a variable
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005

delta

(del -tă) (δ)
1. The fourth letter of the Greek alphabet, used in stellar nomenclature usually to designate the fourth-brightest star in a constellation or sometimes to indicate a star's position in a group.
2. Symbol for declination.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006

delta

[′del·tə]
(anatomy)
A fingerprint focal point which is the point on a ridge at or in front of and nearest the center of the divergence of the type lines.
(electronics)
The difference between a partial-select output of a magnetic cell in a one state and a partial-select output of the same cell in a zero state.
(geology)
An alluvial deposit, usually triangular in shape, at the mouth of a river, stream, or tidal inlet.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

delta

delta
delta
deltaclick for a larger image
i. An aircraft with a triangle-shaped or delta wing. See delta aircraft.
ii. In parachuting, it means a free-fall position where the arms are held in a sweptback position from the shoulder. This position is used for horizontal travel.
iii. An aircraft with delta wing.
delta aircraft An aircraft with a delta (triangular shaped) wing. See delta (iii).
delta hinge The hinge about which the helicopter rotor blades are free to flap in a plane parallel to the hub axis.
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved

Delta

(language)


1. An expression-based language developed by J.C. Cleaveland in 1978.

2. A string-processing language with single-character commands from Tandem Computers.

3. A language for system specification of simulation execution.

["System Description and the DELTA Language", E. Holback-Hansen et al, DELTA Proj Rep 4, Norweg Comput Ctr, Feb 1977].

4. A COBOL generating language produced by Delta Software Entwicklung GmbH.

delta

(2)
A quantitative change, especially a small or incremental one (this use is general in physics and engineering). "I just doubled the speed of my program!" "What was the delta on program size?" "About 30 percent." (He doubled the speed of his program, but increased its size by only 30 percent.)

delta

(3)
[Unix] A diff, especially a diff stored under the set of version-control tools called SCCS (Source Code Control System) or RCS (Revision Control System). See change management.

delta

(4)
A small quantity, but not as small as epsilon. The jargon usage of delta and epsilon stems from the traditional use of these letters in mathematics for very small numerical quantities, particularly in "epsilon-delta" proofs in limit theory (as in the differential calculus). The term delta is often used, once epsilon has been mentioned, to mean a quantity that is slightly bigger than epsilon but still very small. "The cost isn't epsilon, but it's delta" means that the cost isn't totally negligible, but it is nevertheless very small. Common constructions include "within delta of ---", "within epsilon of ---": that is, "close to" and "even closer to".
This article is provided by FOLDOC - Free Online Dictionary of Computing (foldoc.org)

delta

An incremental value between one number and another.
Copyright © 1981-2019 by The Computer Language Company Inc. All Rights reserved. THIS DEFINITION IS FOR PERSONAL USE ONLY. All other reproduction is strictly prohibited without permission from the publisher.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Delta

 

a lowland in the lower reaches of a river, made up of river sediments and dissected by a more or less ramified network of arms and channels. The name “delta” is derived from the capital letter of the Greek alphabet Δ (delta). Because of its resemblance to the Greek letter, the triangular lowland near the mouth of the Nile River was called a “delta” in antiquity.

Deltas are formed as a result of the complex interaction of river discharge, wave motion, tides, and wind-driven onshore and offshore currents. The formation of a delta where there is a shallow beach begins with the appearance of spits near the mouth and underwater bars (deposits) in the riverbed or bars (estuarine bars, “alluviums”) at the edge of the sea. At high water, the deposits and estuarine bars gradually appear above the water and become low-lying islands that divide the riverbed into arms. Where the coastline is deeper, river-borne sediment is built by the waves into shoreline embankments that border the seaward edge of the delta.

Favorable conditions for the rapid growth of a delta are an abundance of sediment deposited by a river, in some cases the lowering of the level of the waterway (or the tectonic elevation of the bank), the location of the river mouth at the apex of a bay or in a lagoon (obstructed deltas), and the shallowness of the basin into which a river discharges. The formation of deltas is impeded by strong tidal currents, wind-driven onshore and offshore currents, and the rapid elevation of the level of the body of water (rapid tectonic submergence). The rate of growth of deltas varies widely from several meters to hundreds of meters a year. For example, while the level of the Caspian Sea remained stable (1863-1914), the linear growth of the Volga delta was 94 m a year, but between 1930 and 1940, the delta grew by up to 0.7-1 km per year.

Deltas evolving in the apexes of bays are called fill deltas, and those that develop on an open seacoast are called protruding deltas. A number of types of deltas are classified according to the method of formation and the stages of development: cuspate deltas (the Tiber), bird-foot deltas (the Mississippi), obstructed deltas (the Kamchatka), protruding deltas with an open, rounded seaward edge (the Niger), and multi-island deltas (the Volga). When there is a small quantity of sediment and the sea level drops, the river arms dissect the deposits that make up the surface of the estuarine section of land, which is of marine or other origin, and serrated deltas are formed (the Neva).

The deltas of major rivers are often large: the area of the Amazon delta is 100,000 sq km, the Lena delta, 28,500 sq km, and the Volga delta, 19,000 sq km. The fertility of the soils and their moisture make lands of a sizable portion of many deltas very valuable as areas for intensive farming (for example, the deltas of the Nile, the Huang, and the Ganges).

REFERENCES

Samoilov, I. V. Ust’ia rek. Moscow, 1952.
Leont’ev, O. K. Osnovy geomorfologii morskikh beregov i dna. Moscow, 1961.
Zalogin, B. S., and N. A. Rodionov. Ust’evye oblasti rek SSSR. Moscow, 1969.

O. K. LEONT’EV

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
The estuarine and deltaic deposits are probably marine in origin and, in the field, these deposits can usually be differentiated from the overlying floodplain deposits because the former has a very soft consistency, has a gritty feel when rubbed between the fingers, greenish gray to dark bluish gray or bluish gray in colour, is saturated or very wet in appearance and is sometimes accompanied by marine shell fragments (Lam, 1989).
Most of the petroleum there is reservoired in deltaic sandstones contained in anticlinal structures.
The river discharge in the deltaic region has now reduced to about one-fifth and the river has been confined to a single channel almost down to the coastal area.
of deltaic swamps along the coastal belt of Khulna, the Sundarbans is also the natural habitat of spotted deer, crocodiles, monkeys, cheetahs, pythons, wild boars and different species of colorful birds making it a paradise for the eco-tourist.
Breton Sound is a 271,000-ha microtidal estuary located in the Mississippi River deltaic plain of southeast Louisiana; it is bounded to the east by the Mississippi River Gulf Outlet (MRGO) and to the west by the Mississippi River (Fig.
Catch per unit effort for the oyster reef, tidal river, and deltaic habitats were 0.59, 0.19, and 0.0, respectively.
Recent work to re-examine the paleoenvironment of the Campbellton Formation (Kennedy and Gibling 2011, and references therein) has resulted in the "Atholville Beds" being attributed to a coastal deltaic setting, with a marine influence, as demonstrated by rare occurrences of prasinophytes (tasmanitids) and acritarchs (Blieck and Cloutier 2000).
NONAGRAM: acid; acted; cadet; cadge; cadi; cage; caged; ceil; celt; citadel; cite; cited; clad; cleat; cleg; dace; decal; delict; deltaic; dialect; dice; clat; edict; glac; glaciate; GLACIATED; iced; lace; laced; laic; talc.
'Populations in low-lying islands and deltaic regions are particularly at risk,' he says.
(3) The restoration of coastal Louisiana, one of the great deltaic ecosystems of the world, which has lost 2,000 square miles of coastal marshes and swamp forests in the past 100 years, should be a national water resources investment priority.
With Ngege-1 opening up a new deltaic play fairway with high quality reservoir we are very encouraged by the potential of this programme in the north of Block 2.'