delta
UK[ˈdeltə]US[ˈdeltə]
n
The fourth letter of the Greek alphabet (Δ, δ)
n
A triangular area of land where a major river divides into several smaller parts that flow into a sea or lake
n
A difference between two things or values, especially in mathematics or finance
Etymology
The word 'delta' entered English in the mid-16th century directly from the Greek letter name 'delta' (δέλτα). The Greeks themselves derived this name from the Phoenician letter 'daleth', meaning 'door', likely due to the triangular shape of the letter's opening. The application of 'delta' to describe a river's triangular mouth is attributed to the historian Herodotus in the 5th century BC, who noted the resemblance between the shape of the Nile's river mouth and the form of the Greek letter Δ. This geographical sense was later adopted into scientific English, and the term has since been extended metaphorically into fields like mathematics and finance to denote a difference or change.
Analysis
The word 'delta' is a simplex loanword from Greek. It is not productively segmented into smaller meaningful parts within modern English spelling.
Examples
The Nile Delta is a fertile agricultural region.
The delta between the forecast and the actual sales figures was significant.
In physics, the symbol Δ is used to represent change.