Delta (letter)

Delta (/ˈdɛltə/;[1] uppercase Δ, lowercase δ; Greek: δέλτα, délta, [ˈðelta])[2] is the fourth letter of the Greek alphabet.

[3] Letters that come from delta include the Latin D and the Cyrillic Д.

Contrary to a popular legend,[vague] this use of the word delta was not coined by Herodotus.

[4] In Ancient Greek, delta represented a voiced dental plosive IPA: [d].

In Modern Greek, it represents a voiced dental fricative IPA: [ð], like the "th" in "that" or "this" (while IPA: [d] in foreign words is instead commonly transcribed as ντ).