del·​ta | \ ˈdel-tə How to pronounce delta (audio) \

Essential Meaning of delta

1 : the fourth letter of the Greek alphabet
2 : a piece of land shaped like a triangle that is formed when a river splits into smaller rivers before it flows into an ocean a river delta the Ganges/Nile Delta
3 US : an area of low land along the Mississippi River that is mainly in the state of Mississippi the Mississippi Delta delta blues [=blues music that comes from the Mississippi delta]

Full Definition of delta

 (Entry 1 of 5)

1 : the 4th letter of the Greek alphabet — see Alphabet Table
2 : something shaped like a capital Greek delta especially, geology : the alluvial deposit at the mouth of a river the Mississippi Delta
3 mathematics : an increment of a variable symbol Δ

Definition of delta (Entry 2 of 5)

: fourth in position in the structure of an organic (see organic entry 1 sense 1b(2)) molecule from a particular group or atom symbol ƍ


communications code word

Definition of Delta (Entry 3 of 5)

used as a code word for the letter d

Definition of Delta (Entry 4 of 5)

: of, relating to, or characteristic of the The Delta region of Mississippi


geographical name
Del·​ta | \ ˈdel-tə How to pronounce Delta (audio) \

Definition of Delta (Entry 5 of 5)

1 municipality south and southeast of Vancouver in southwestern British Columbia, Canada population 99,863
2 see delta, the

Other Words from delta


deltaic \ del-​ˈtā-​ik How to pronounce Delta (audio) \ adjective

First Known Use of delta


13th century, in the meaning defined at sense 1

Adjective (1)

circa 1929, in the meaning defined above

Communications code word

1952, in the meaning defined above

Adjective (2)

1859, in the meaning defined above

History and Etymology for delta

Noun and Adjective (1)

Middle English deltha, from Greek delta, of Semitic origin; akin to Hebrew dāleth daleth

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Time Traveler for delta

Time Traveler

The first known use of delta was in the 13th century

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Cite this Entry

“Delta.” Dictionary, Merriam-Webster, Accessed 27 Oct. 2021.

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More Definitions for delta


del·​ta | \ ˈdel-tə How to pronounce delta (audio) \

Kids Definition of delta

: a piece of land in the shape of a triangle or fan made by deposits of mud and sand at the mouth of a river


del·​ta | \ ˈdel-tə How to pronounce delta (audio) \

Medical Definition of delta

 (Entry 1 of 2)

1 : the fourth letter of the Greek alphabet symbol Δ or ƍ
2 : any of various things felt to resemble a capital Δ especially : the triangular terminus of a pattern in a fingerprint formed either by bifurcation of a ridge or by divergence of two ridges that are parallel beyond it


variants: or ƍ-

Medical Definition of delta (Entry 2 of 2)

1 : of or relating to one of four or more closely related chemical substances the delta chain of fetal hemoglobin ƍ-yohimbine used somewhat arbitrarily to specify ordinal relationship or a particular physical form and especially one that is allotropic, isomeric, or stereoisomeric (as in ƍ-benzene hexachloride)
2 : fourth in position in the structure of an organic molecule from a particular group or atom also : having a structure characterized by such a position ƍ-hydroxy acids ƍ-lactones

More from Merriam-Webster on delta

Nglish: Translation of delta for Spanish Speakers

Britannica English: Translation of delta for Arabic Speakers Encyclopedia article about delta


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