delta

Pronunciation

• IPA: /ˈdɛltə/^[1]

Etymology

It is borrowed from Ancient Greek δέλτα (délta), the name of the fourth letter of the Greek alphabet,^[2][3][4] which is of Semitic origin: compare Phoenician and Hebrew dāleth, from deleth, door, originally drawn as the door of a tent.^[2][3][5]

Earliest recorded meaning

The name of the Greek letter: probably about 1200, in the Ormulum.^[2][3]

Semantic evolution

The letter was shaped like a triangle, and Herodotus used the name for the triangular land at the mouth of the Nile, a sense introduced into Greek in the 400s BC.^[3][2] The Delta of the Nile is so called in English from 1555 (the 1550s),^[2][6] and other river mouths of whatever shape by 1790.^[3][6] Any triangular figure is from 1638.^[6] An examiner's fourth-class mark is from 1911,^[6] and in electrical equipment a triangular arrangement of three-phase windings from 1902.^[6] Word Origins notes that the delta wing of jet aircraft was named immediately after the Second World War.^[7]

Timeline

• c. 1200 – the Greek letter.^[2]
• 1555 – the Nile Delta.^[2]
• 1638 – a triangular figure.^[6]
• 1790 – any river delta.^[6]
• 1902 – in electrical engineering.^[6]

Modern meaning

Noun

1. The fourth letter of the Greek alphabet (Δ, δ).
2. A flat, usually triangular area of alluvial land at the mouth of a river.
3. An object shaped like a triangle.
4. (mathematics) A finite increment in a variable.

Word family

• deltaic
• delta connection
• delta iron
• delta particle
• delta ray
• delta wave
• delta wing
• Dirac delta function

Related words

• deltoid
• daleth
• alphabet

References

1. ^ Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
3. ^ a b c d e Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
4. ^ Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
5. ^ Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
6. ^ a b c d e f g h Simpson, J. A.; Weiner, E. S. C., eds. (1989), The Oxford English Dictionary, 2nd ed., Oxford: Clarendon Press
7. ^ Cresswell, Julia (2021), Oxford Dictionary of Word Origins, 3rd ed., Oxford: Oxford University Press