ETYM Greek delta, the name of the fourth letter of the Greek alphabet (the capital form of which is andDELTA;, Eng. D), from the Phoenician name of the corresponding letter.
The 4th letter of the Greek alphabet.
Fourth letter of Greek alphabet (D,d).

A low triangular area where a river divides before entering a larger body of water.
D-shaped area of alluvium at river-mouth.
Tract of land at a river’s mouth, composed of silt deposited as the water slows on entering the sea. Familiar examples of large deltas are those of the Mississippi, Ganges and Brahmaputra, Rhône, Po, Danube, and Nile; the shape of the Nile delta is like the Greek letter delta D, and thus gave rise to the name.
The arcuate delta of the Nile is only one form. Others are birdfoot deltas, like that of the Mississippi which is a seaward extension of the river’s levee system; and tidal deltas, like that of the Mekong, in which most of the material is swept to one side by sea currents.

Fourth in position in the structure of an organic molecule from a particular group or atom

1. Borough in Pennsylvania (USA); zip code 17314.
2. City in Colorado (USA); zip code 81416.
3. City in Iowa (USA); zip code 52550.
4. City in Missouri (USA); zip code 63744.
5. City in Utah (USA); zip code 84624.
6. Village in Louisiana (USA).
7. Village in Ohio (USA); zip code 43515.