Tau

History Diacritics and other symbols Related topics

• Use as scientific symbols
• Orthography
• Romanization
• Cyrillization

Tau (; uppercase Τ, lowercase τ or τ; Greek: ταυ) is the nineteenth letter of the Greek alphabet, representing the voiceless dental or alveolar plosiveIPA:. In the system of Greek numerals, it has a value of 300.

The name in English is pronounced or , and in Greek it is . This is because the pronunciation of the combination of Greek letters αυ can have the pronunciation of either [ai], [av] or [af], depending on what follows and if a diaeresis is present on the second vowel or an accent mark is present on the first vowel in Greek orthography.

Tau was derived from the Phoenician lettertaw (𐤕). Letters that arose from tau include Latin T and Cyrillic Te (Т, т).