Other forms: deltas
A delta is the fan of land and channels where a river meets the sea. The Nile delta, a river delta, the delta region.
It forms where a river slows and drops the silt it has carried, splitting into branches called distributaries. Deltas are extremely fertile and extremely vulnerable — many of the world's most crowded farmlands are deltas, and most are sinking or eroding. Delta is also the fourth letter of the Greek alphabet, and in mathematics and science it stands for a change in a quantity. Note delta wing, the triangular aircraft shape.
1noundeltaThe fan of land and channels where a river meets the sea.
“The delta covers about twenty-four thousand square kilometres.”
2nounfourthThe fourth letter of the Greek alphabet, used for change.
“The delta between the two figures is what matters.”
delta is a landform, or a letter.
Greek delta is the letter, written as a triangle. Herodotus named the Nile's mouth after the letter's shape, and every river delta in the world is therefore named after a piece of the Greek alphabet.
Proto-Semitic
*dalt-
Ancient Greek
δέλτα
English, today
delta
From Ancient Greek δέλτα, borrowed from a Phoenician word for "door", ultimately from Proto-Semitic dalt-. a doublet of dalet.
Etymology from Wiktionary, CC BY-SA
Practised in Nature & Weather