Greek letters are the letters used in Greek, and are also widely used in mathematics, physics, biology, chemistry, astronomy and other disciplines. The Greek alphabet is similar to the Latin alphabet and Cyrillic alphabet and is a whole phoneme character. Greek alphabet is the earliest writing system in the world that has letters representing vowels and phonemes.
The Cyrillic and Georgian letters used in Russian and Ukrainian are developed from Greek letters. Some words related to Greek letters in Greek have entered many languages. For example, delta comes from Greek letters Δ， because Δ The shape of the is a triangle.