ASCII Character תHebrew letter Tav
Taw, tav, or taf is the twenty-second and last letter of the Semitic abjads, including the Hebrew alphabet. Taw is believed to be derived from the Egyptian hieroglyph representing a tally mark (viz. a decussate cross). The letter tav in Modern Hebrew usually represents a voiceless alveolar plosive: /t/. The letter tav is one of the six letters that can receive a dagesh kal diacritic; the others are bet, gimel, dalet, kaph and pe. In gematria, tav represents the number 400, the largest single number that can be represented without using the sophit (final) forms (see kaph, mem, nun, pe, and tzade).