Delta
/ˈdɛltə/noun
The triangle of silt where a river splits into channels and meets the sea, or the fourth letter of the Greek alphabet.
The Greek roots
Literally: “the letter delta”
The story of the word
Herodotus made the leap, calling the flat land at the mouths of the Nile "the Delta" because it has the shape of a capital Δ. The letter's own name is Phoenician daleth, a door, since the alphabet was Phoenician before it was Greek. Mathematics reads the letter as the initial of difference, small δ for a tiny change and capital Δ for a gap between two values. Aircraft took the delta wing in the 1930s from the same triangle.
- How it travelled
- Ancient Greek → Latin → English
- First recorded
- 16th century
The same roots elsewhere
Other languages reached for exactly the same Greek pieces.
Same family
In a sentence
Half the delta is under water for two months of the year.
The delta between forecast and outturn was almost nine percent.