There are 2 main definitions of delta in English:

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delta 1

Syllabification: del·ta
Pronunciation: /ˈdeltə/


1The fourth letter of the Greek alphabet (Δ, δ), transliterated as ‘d.’.
Example sentences
  • Other symbols use in chemistry include the Greek letter delta to denote a change in energy levels and an arrow to indicate the direction a reaction proceeds in.
  • Casey guessed the next would be delta: phonetic alphabet
  • Apparently they don't teach you anything useful, just epsilons and deltas.
1.1 [as modifier] The fourth in a series of items, categories, etc. delta hepatitis
More example sentences
  • The study reports the influence of delta infection on the severity of hepatitis B.
  • To me it looked like the alpha males on the rampage, and alpha males are always scary to all the gamma and delta males.
  • Our results suggest that delta infection may not be very common in Indian patients with HBV-related liver diseases.
1.2 (Delta) [followed by Latin genitive] Astronomy The fourth (usually fourth-brightest) star in a constellation: Delta Cephei
More example sentences
  • Other bright stars in Canis Major are Adhara (Epsilon Canis Majoris), Mirzam (Beta Canis Majoris), and Wezen (Delta Canis Majoris).
  • As a connecting star to Pegasus, it is also known as Delta Pegasi, though this name is rarely used.
2A code word representing the letter D, used in radio communication.
Example sentences
  • Pilot: Regina Tower, (this is) Cessna foxtrot bravo charlie delta (over).


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1 (δ) Mathematics Variation of a variable or function.
2 (Δ) Mathematics A finite increment.
3 (δ) Astronomy Declination.

Words that rhyme with delta

belter, helter-skelter, melter, pelta, Shelta, shelter, swelter, welter
Definition of delta in:
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There are 2 main definitions of delta in English:

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delta 2 Syllabification: del·ta
Pronunciation: /ˈdeltə/


1A triangular tract of sediment deposited at the mouth of a river, typically where it diverges into several outlets.
Example sentences
  • It and many other old zircons come from metamorphosed sediments deposited in river deltas some 3 billion years ago in what is now southwestern Australia.
  • Discriminating between deposits of tidally influenced deltas and tide-dominated coastal mud flats in the rock record is often difficult.
  • Innumerable lagoons, lakes, canals, estuaries and the deltas of 44 rivers make up the 900 km of backwater network of the State.
1.1 (the Delta) A region in northern Mississippi that lies between the Yazoo and Mississippi rivers and is known for its cotton and for blues music. Also called Yazoo Delta or Mississippi Delta.


Pronunciation: /delˈtāik/
Example sentences
  • Flows may have been storm-triggered or represent hyperpycnal underflows sourced from deltaic distributary channels, indicating the proximity of the coastline.
  • Unlike the deltaic, lowland assemblages of the southwestern United States, the Bromacker assemblage contains neither fish nor obligate aquatic tetrapod remains.
  • Avery Island is actually a small hill, created in the deltaic wetlands by the upwelling of ancient salt deposits that exist beneath the Mississippi Delta.


Mid 16th century: originally specifically as the Delta (of the Nile River), from the shape of the Greek letter (see delta1).

  • The triangular area of sediment at the mouth of some rivers takes the name delta from its shape, which is like that of the triangular fourth letter of the Greek alphabet, called delta. The original delta was at the mouth of the River Nile, which was called the Delta from the mid 16th century. The shape of the Greek letter also gave its name to the delta wing, a triangular swept-back wing fitted on some jet aircraft, immediately after the Second World War.

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