Initial

In a written or published work, an initial or drop cap is a letter at the beginning of a word, a chapter, or a paragraph that is larger than the rest of the text. The word is comes from the Latin "initialis", which means "standing at the beginning". An initial is often several lines in height and in older books or manuscripts. In some cases a name or title can be long so the initials would shorten them.
Examples include: JFK, FDR, AOC, TDK, NYC, USA, KUWTK, EU, etc.