Greek letters, capital and small

LETTERS OF GREEK ALPHABET
name
The letters of the greek alphabet derive from the phoenician alphabet. Their names too.
See HISTORY of GREEK.
The etymology of each letter's name is discussed: alpha, beta, etc. The phoenician meaning of the names is not related to any greek words. E.g. aleph in phoenician means ox, but alpha in greek means just alpha and has nothing to do with oxen.
gender of name
During the byzantine times, the letter names were feminine nouns, preceded by the feminine article «η».
Today, the letter names are neutral nouns preceded by the neutral article «τo». These nouns are not inflected. Note that aclesia (=no declension) is a very rare phaenomenon in greek that occurs for foreign words.
typeface
Majuscula (capital) letter.
See ancient typeface of alphabet.
Minuscula (lowercase, small) letter.
See HISTORY of GREEK - hellenistic innovations.