# Δ

| Δ | U+0394, &#916; GREEK CAPITAL LETTER DELTA |
| ← Γ [U+0393] | Greek and Coptic | Ε → [U+0395] |

## Translingual
### Symbol

Δ
* (mathematics, sciences) Alternative form of ∆: change in a variable
* (chemistry) Used on the reaction arrow in a chemical equation, to show that energy in the form of heat is added to the reaction
* (mathematics, set theory) Used to represent the symmetric difference (also known as the disjunctive union) of two sets
* (genetics) Used before a gene name as a modifier to denote a deletion mutation of that gene.
* (music) Used after a pitch class to denote a major seventh chord with a note of said pitch as its root.

#### Usage notes

(mathematics): Unicode establishes a distinct symbol (∆) for particular use in mathematics, but Δ is often substituted for convenience.

#### Coordinate terms

* Δ on Wikipedia.Wikipedia

## English
### Noun

Δ
* (law) Abbreviation of defendant.

## Albanian
### Pronunciation

* IPA: /ð(ə)/

### Letter

Δ (Dh) (upper case Δ, lower case δ)
* The 6th letter of the Arvanitic Albanian Greek-script alphabet.

#### See also

* Greek script letters (script appendix): Α α, Β β, B b, Γ γ, Γϳ γϳ, Δ δ, D d, Ε ε, Ε̱ ε̱, Ζ ζ, Ζ̇ ζ̇, Θ θ, Ι ι, Ϳ ϳ, Κ κ, Κ̇ κ̇, Λ λ, ΛΛ λλ, Λ̇ λ̇, Μ μ, Ν ν, Ν̇ ν̇, Ο ο, Π π, Ρ ρ, Ρ̇ ρ̇, Σ σ, Σ̈ σ̈, Τ τ, Ȣ ȣ, Υ υ, Φ φ, Χ χ, Χ̇ χ̇, ΤΣ τσ, ΤΣ̈ τσ̈, DΣ dσ, DΣ̈ dσ̈
* (Latin-script letters) shkronjë; A a, B b, C c, Ç ç, D d, Dh dh, E e, Ë ë, F f, G g, Gj gj, H h, I i, J j, K k, L l, Ll ll, M m, N n, Nj nj, O o, P p, Q q, R r, Rr rr, S s, Sh sh, T t, Th th, U u, V v, X x, Xh xh, Y y, Z z, Zh zh

## Ancient Greek
### Etymology

From the Phoenician letter 𐤃 (d, “dālet”).

### Letter

Δ • (D) (uppercase, lowercase δ)
* The letter delta (δέλτα (délta)), the fourth letter of the ancient Greek alphabet.

#### Derived terms

* (Cyrillic) Д
* (Coptic) Ⲇ
* (Gothic) 𐌳

#### See also

* (Greek-script letters) Α α, Β β, Γ γ, Δ δ, Ε ε, Ζ ζ, Η η, Θ θ, Ι ι, Κ κ, Λ λ, Μ μ, Ν ν, Ξ ξ, Ο ο, Π π, Ρ ρ, Σ σ ς, Τ τ, Υ υ, Φ φ, Χ χ, Ψ ψ, Ω ω
* (non-Classical letters) Ϝ (W) ϝ (w), Ͷ ͷ, Ͱ (H) ͱ (h), Ϻ (Ś) ϻ (ś), Ϟ, ϟ, Ϙ (Q) ϙ (q), Ͳ (S) ͳ (s)
* (punctuation) · ;
* (diacritics) ᾿ ῾ ◌́ ◌̀ ῀ ¨

## Cypriot Arabic
### Pronunciation

* IPA: /ð/

### Letter

Δ (lower case δ)
* A letter of the Cypriot Arabic alphabet, written in the Latin script.

## Greek
### Adjective

Δ • (D)
* Abbreviation of δυτικός (dytikós, “west, westerly”).

### Noun

Δ • (D)
* Abbreviation of δύση (dýsi, “west”).

#### See also

* Appendix:Greek compass points

### Letter

Δ • (D) (uppercase, lowercase δ)
* The upper case delta (δέλτα), the fourth letter of the modern Greek alphabet, representing a voiced interdental fricative (/ð/).

#### Coordinate terms

* (Greek-script letters) Α α, Β β, Γ γ, Δ δ, Ε ε, Ζ ζ, Η η, Θ θ, Ι ι, Κ κ, Λ λ, Μ μ, Ν ν, Ξ ξ, Ο ο, Π π, Ρ ρ, Σ σ ς, Τ τ, Υ υ, Φ φ, Χ χ, Ψ ψ, Ω ω
* (non-Classical letters) Ϝ (W) ϝ (w), Ͷ ͷ, Ͱ (H) ͱ (h), Ϻ (Ś) ϻ (ś), Ϟ, ϟ, Ϙ (Q) ϙ (q), Ͳ (S) ͳ (s)
* (punctuation) · ;
* (diacritics) ᾿ ῾ ◌́ ◌̀ ῀ ¨

#### Descendants

* (Glagolitic): Ⰴ, ⰴ

#### See also

* Δ΄
* ͵Δ

## Wakhi
### Pronunciation

* IPA: /ð/

### Letter

Δ (lower case δ)
* A letter of the Wakhi alphabet, written in the Latin script.