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Del·ta (dĕltə)
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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.

The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
 
del·ta (dĕltə)
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n.
1. The fourth letter of the Greek alphabet. See Table at alphabet.
2. An object shaped like a triangle.
3.
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 the Appendix of Semitic roots.]

del·taic (-tāĭk), deltic (-tĭk) adj.
(click for a larger image)
delta
satellite image of the
Nile River delta, Egypt

The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
 

Indo-European & Semitic Roots Appendices

    Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:

    Indo-European Roots

    Semitic Roots

    The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.

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