Koppa

Koppa (Ϙ ϙ) is an archaic letter of the Greek alphabet that appears in some early Greek writings. It was used to represent the voiceless velar stop /k/ in certain dialects, particularly before back vowels such as o, u, and a. In many dialects, including later Attic Greek, the /k/ sound came to be written exclusively with kappa (κ), and koppa eventually fell out of use as a letter.

Two standard forms of the symbol exist: a capital form Ϙ and a lowercase form ϙ. The name koppa is the traditional designation for this sign in the Greek alphabet, and its origins are typically linked to the broader family of Phoenician-derived letters from which Greek borrowed its early signs. The exact historical relationship between koppa and other early k-sounds in Greek is debated, but it is generally understood that koppa functioned alongside kappa in some dialects before being abandoned as a distinct letter.

In addition to its occasional use as a letter, koppa was preserved as a numerical symbol in the system of Greek numerals, where it represented the value 90. This numeric function persisted even after koppa ceased to be used as a letter in most writing. In later periods, the primary symbol for the /k/ sound remained kappa, and koppa survived mainly in epigraphic or numerical contexts rather than in everyday orthography.

Today, koppa is described in scholarly sources as an archaic element of the Greek alphabet. It is studied primarily for its historical and philological significance in the evolution of Greek writing and the development of Greek numerals.