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satellite image of the
Nile River delta, Egypt


1. The fourth letter of the Greek alphabet. See Table at alphabet.
2. An object shaped like a triangle.
a. A usually triangular alluvial deposit at the mouth of a river.
b. A similar deposit at the mouth of a tidal inlet, caused by tidal currents.
4. Mathematics A finite increment in a variable.
adj. Chemistry
1. Being in the fourth position relative to a designated carbon atom in an organic molecule at which an atom or a group may be substituted.
2. Referring to the fourth of a group of isomers, or molecules of similar origin or properties, determined arbitrarily by those who discover or classify them. Used in combination.

[Middle English, from Latin, from Greek, of Phoenician origin; see dl in Semitic roots.]

del·ta′ic (-tā′ĭk), del′tic (-tĭk) adj.


An area of the south-central United States extending on either side of the Mississippi River from Memphis, Tennessee, to Vicksburg, Mississippi. An important cotton-producing region, it is noted for its folk culture, especially as the home of some of the earliest blues music.
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References in periodicals archive ?
Distributary channels associated with a deltaic system subsequently delivered fresh water that resulted in deposition of brackish water gray shales.
The Sundarbans is a UNESCO World Heritage site and the largest deltaic mangrove forest in the world with an area of 10,200 sq.
Louisiana's mottled ducks make up well over half of the region's total because of its massive expanse of soft deltaic and chenier plain marshes.
The Lindsea Bea Conglomerate formation is from the Lower Pennsylvanian System, a major producing deltaic movement within the study area.
Also, low lying deltaic countries like Bangladesh and many small island states are likely to be severely affected.
Both cities rose out of swampy, low-lying land along a river (although hills surrounding Cork differed from the flat deltaic lands around Calcutta).
The indications of tidal processes suggest that these deposits are not alluvial and have formed in deltaic or estuarine settings.
These previously discovered eurypterids are from the western exposure of the Campbellton Formation and are believed to have inhabited a coastal deltaic setting, along with a rich vertebrate assemblage that included cephalaspids, placoderms, acanthodians, and sharks.
Soviet and Cuban engineers built thousands of miles of canals and culverts that worked with Swiss precision to irrigate and drain the immense rice fields growing in a low deltaic plain with rich clayey soils near the mouth of the Zaza and Jatibonico rivers along Cuba's southern coast.
The uppermost member of the Woodbine Formation is a coastal deltaic unit referred to as the Arlington Member (Oliver 1971; Main 2005; 2009).
Populations in low-lying islands and deltaic regions are particularly at risk,' he says.
In such cases as Bangladesh, Egypt, Guyana, and Vietnam, where nearly half or more of the populations live in low-lying deltaic regions that support a major fraction of their economies, SLR will threaten the very functioning of the state.