2520: Koppa Ϙ/ϙ Nov 6, 2021

The Phoenician abjad, which is the origin of the Greek alphabet, contained certain letters for sounds that in Greek didn't exist. The Phoenician qoph (pronounced [q]) didn't exist in Greek, and since Greek could already use Κ (kappa) the Greek letter koppa (Ϙ, ϙ) was used before back-vowels. This practice was retained in Etruscan and Italic languages for a while, but unlike Q, which also came from this same Phoenician letter, Ϙ in Greek didn't survive, except sometimes for numerical purposes to represent 90. It is a similar story with the Cyrillic koppa (Ҁ ҁ) which is also now archaic.