delta

¹ American  

[del-tuh] / ˈdɛl tə /

noun

1. the fourth letter of the Greek alphabet (Δ, δ).

2. the consonant sound represented by this letter.

3. the fourth in a series of items.

4. anything triangular, like the Greek capital delta (Δ).

5. Mathematics. an incremental change in a variable, as Δ or δ.

6. a nearly flat plain of alluvial deposit between diverging branches of the mouth of a river, often, though not necessarily, triangular.

   the Nile delta.

7. Also Delta a word used in communications to represent the letter D.

8. Astronomy. Delta, a star that is usually the fourth brightest of a constellation.

   The fourth brightest star in the Southern Cross is Delta Crucis.

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Delta ² American  

[del-tuh] / ˈdɛl tə /

noun

Military.

1. the NATO name for a class of nuclear-powered submarines armed with multiple-warhead ballistic missiles, including those designed to strike military and industrial installations: first produced for the Soviet Navy in the 1970s; in service with the Russian Navy since 1992.

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delta ¹ British  

/ dɛlˈteɪɪk, ˈdɛltə /

noun

1. the fourth letter in the Greek alphabet (Δ, δ), a consonant transliterated as d

2. an object resembling a capital delta in shape

3. (capital when part of name) the flat alluvial area at the mouth of some rivers where the mainstream splits up into several distributaries

   the Mississippi Delta

4. maths a finite increment in a variable

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Delta ² British  

/ ˈdɛltə /

noun

1. (foll by the genitive case of a specified constellation) usually the fourth brightest star in a constellation

2. any of a group of US launch vehicles used to put unmanned satellites into orbit

3. communications a code word for the letter d

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Delta ³ British  

/ ˈdɛltə /

noun

1. a state of Nigeria, on the Niger river delta on the Gulf of Guinea. Capital: Asaba. Pop: 4 098 391 (2006). Area: 17 698 sq km (6833 sq miles)

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delta Scientific  

/ dĕl′tə /

1. A usually triangular mass of sediment, especially silt and sand, deposited at the mouth of a river. Deltas form when a river flows into a body of standing water, such as a sea or lake, and deposits large quantities of sediment. They are usually crossed by numerous streams and channels and have exposed as well as submerged areas.

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Other Word Forms

• deltaic adjective

Etymology

Origin of delta

First recorded in 1150–1200; Middle English delta, deltha, from Latin delta, from Greek délta; akin to Hebrew dāleth

Example Sentences

With desert accounting for most of the country's million square kilometres, the vast majority of Egypt's 108 million people -- the Arab world's largest population -- are stacked vertically along the Nile River and its delta.

From Barron's

Given the nature of delta hedging options, their activity, especially when approaching option expiry, can amplify or exaggerate market moves significantly.

From MarketWatch

Bureau of Reclamation recently notified California agencies that it plans to pump more water out of the delta into the southbound aqueducts of the federally operated Central Valley Project.

From Los Angeles Times

Perseverance was dispatched to the Jezero Crater because it showed qualities that may have meant it was once conducive to life, including signs it was once a delta when Mars could sustain liquid surface water.

From BBC

Ms. Low rehashes that old story, but concedes the delta is at least partially a product of the fact that “many women want to spend time at home with their children.”

From The Wall Street Journal

Related Words

• box
• cavity
• door
• entrance
• gate
• rim