delta

¹

[ del-tuh ]

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

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

Delta

²

[ del-tuh ]

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.

delta

¹

/ 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

Delta

²

/ 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)

Delta

³

/ 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

delta

/ 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.

Derived Forms

• deltaic, adjective

Word History and Origins

Origin of delta¹

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

Word History and Origins

Origin of delta¹

C16: via Latin from Greek, of Semitic origin; compare Hebrew dāleth

Example Sentences

In recent years, Los Angeles has been importing nearly 90% of its water, drawing on supplies from the Eastern Sierra, the Sacramento-San Joaquin River Delta and the Colorado River.

From Los Angeles Times

He has said the resource is “horribly mismanaged” in California and has promised to turn on a massive “faucet” for farmers and cities — partly by weakening environmental protections for such species as the Delta smelt.

From Los Angeles Times

Speaking at his Rancho Palos Verdes golf club in September, Trump indicated he would revive his first-term fight with California leaders over water allocations and environmental laws meant to protect endangered fish such as the tiny delta smelt.

From Los Angeles Times

The recent discovery of a new type of invasive mussel in the Sacramento-San Joaquin River Delta is raising concerns that the non-native species could cause major ecological harm and inflict costly complications for the infrastructure California relies on to deliver water across the state.

From Los Angeles Times

The mussels were also recently found in O’Neill Forebay, part of the state’s water delivery system south of the Delta near Santa Nella.

From Los Angeles Times

Related Words

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