delta

1 of 4

noun

del·​ta ˈdel-tə How to pronounce delta (audio)
plural deltas
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
4
: delta wave
During deep sleep, the brain operates in delta wave frequency. But it's difficult to go from beta to theta then delta without first switching down to a relaxed alpha state.Daily Mail (London)
5
or less commonly Delta : delta variant
As SARS-CoV-2 continues to spread among humans, natural selection and adaptation will result in more variants that could plausibly be more transmissible than delta.Suresh V. Kuchipudi
deltaic adjective

delta

2 of 4

adjective (1)

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

Delta

3 of 4

communications code word

used as a code word for the letter d

Delta

4 of 4

adjective (2)

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

Examples of delta in a Sentence

Recent Examples on the Web
Noun
Mint's Colorful Life Delta Kite for Kids $24 $17 If there was ever a classic outdoor toy that has stood the test of time, the delta kite is it. Laura Lu, Parents, 7 Mar. 2024 Jezero is a meteorite impact crater believed to have once been flooded with water and home to an ancient river delta. Robert Patalano, Discover Magazine, 9 Feb. 2024 Simply look at the delta between what Tesla does and GM. Andrew Stuttaford, National Review, 5 Feb. 2024 Manufactured by one of the best delta 8 brands, this disposable vape pen has three flavor options and offers moderately intense buzzing highs. Sponsored Content, The Mercury News, 10 Jan. 2024 Even the laws around age limits for buying delta products are confusing. Eleanor Dearman, Fort Worth Star-Telegram, 23 Jan. 2024 Make sure to check the source of the delta 8 before making a purchase. Amber Smith, Discover Magazine, 7 Sep. 2023 Where the Colorado River enters Lake Mead, a delta is being formed. Alka Tripathy-Lang, Ars Technica, 11 Jan. 2024 Water is never in balance in Bangladesh, where rivers flowing from the Himalayas converge in the world’s largest delta. Melanie Stetson Freeman, The Christian Science Monitor, 9 Nov. 2023

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'delta.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

Etymology

Noun and Adjective (1)

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

First Known Use

Noun

12th 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

Time Traveler
The first known use of delta was in the 12th century

Dictionary Entries Near delta

Cite this Entry

“Delta.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/delta. Accessed 19 Mar. 2024.

Kids Definition

delta

noun
del·​ta
ˈdel-tə
1
: the 4th letter of the Greek alphabet
Δ or ƍ
2
: something shaped like a capital Δ
especially : the triangular or fan-shaped piece of land made by deposits of mud and sand at the mouth of a river
deltaic
del-ˈtā-ik
adjective

Medical Definition

delta

1 of 2 noun
del·​ta ˈdel-tə How to pronounce delta (audio)
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
3
4
also Delta : delta variant

delta

2 of 2 adjective
variants or ƍ-
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

Geographical Definition

Delta

geographical name

Del·​ta ˈdel-tə How to pronounce Delta (audio)
1
municipality south and southeast of Vancouver in southwestern British Columbia, Canada population 99,863
2

More from Merriam-Webster on delta

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