Acrophony

Acrophony (/əˈkrɒfəni/; Greek: ἄκρος akros uppermost + φωνή phone sound) is the naming of letters of an alphabetic writing system so that a letter's name begins with the letter itself. For example, Greek letter names are acrophonic: the names of the letters α, β, γ, δ, are spelled with the respective letters: αλφα (alpha), βήτα (beta), γάμμα (gamma), δέλτα (delta).