The repertoire of glyphs is based on the uncial Greek alphabet, augmented by letters borrowed from the Egyptian Demotic.

As early as the sixth century BC and as late as the second century AD, an entire series of pre-Christian religious texts were written in what scholars term Old Coptic, Egyptian language texts written in the Greek alphabet.

With the spread of early Christianity in Egypt, knowledge of Egyptian hieroglyphs was lost by the late third century, as well as Demotic script slightly later, making way for a writing system more closely associated with the Coptic Orthodox Church.

Various scribal schools made limited use of diacritics: some used an apostrophe as a word divider and to mark clitics, a function of determinatives in logographic Egyptian; others used diereses over ⲓ and ⲩ to show that these started a new syllable, others a circumflex over any vowel for the same purpose.

[2] The Coptic script's glyphs are largely based on the Greek alphabet, another help in interpreting older Egyptian texts,[3] with 24 letters of Greek origin; 6 or 7 more were retained from Demotic, depending on the dialect (6 in Sahidic, another each in Bohairic and Akhmimic).

While initially unified with the Greek alphabet by Unicode, a proposal was later accepted to separate it, with the proposal noting that Coptic is never written using modern Greek letter-forms (unlike German, which may be written with Fraktur or Roman Antiqua letter-forms), and that the Coptic letter-forms have closer mutual legibility with the Greek-based letters incorporated into the separately encoded Cyrillic alphabet than with the forms used in modern Greek.

(none) In Old Coptic, there were a large number of Demotic Egyptian characters, including some logograms.

Most fonts contained in mainstream operating systems use a distinctive Byzantine style for this block.