Tau: The Coptic Letter (Value 300), from Greek Tau

Tau is the twentieth letter of the Coptic alphabet and carries the numeral value three hundred; Coptic Orthodox usage names it tav. It writes the t sound and it is one of the busiest letters in the language, because Coptic marks a feminine singular noun as definite with an element built on tau, and the same letter appears in demonstratives, possessives and a range of verbal prefixes. Together with pi, which does the same work for masculine nouns, it is among the first things a student of Coptic learns.

The letter also has a symbolic history older than Coptic and inherited along with the shape. Its Phoenician ancestor was called taw and meant a mark, and in the early Semitic alphabets it was drawn as a cross. That form and that meaning gave the letter a long afterlife in Jewish and then Christian symbolism, in which the last letter of the alphabet, drawn as a cross and standing for a mark set on a person, carried a weight far beyond its phonetic value. Coptic Christianity, whose crosses appear on manuscripts, textiles, buildings and bodies, sits squarely inside that inheritance, although Coptic tau took its place in the middle of the alphabet rather than at the end because the Greek series had extended past it.