Aleph is the first letter of the Hebrew alphabet and one of the three mother letters. Its name means 'ox' and its earliest pictograph was an ox-head; its gematria value is 1. Aleph is a silent letter, a glottal carrier that takes whatever vowel is pointed beneath it, and this silence made it, for the Kabbalists, an emblem of the unspeakable unity of God and of pure potential before articulated speech.
The Sefer Yetzirah (Book of Formation), the foundational text of Jewish letter-mysticism compiled in late antiquity, divides the twenty-two Hebrew consonants into three groups: three 'mother' letters (Aleph, Mem, Shin) assigned to the elements Air, Water and Fire; seven 'double' letters, each with a hard and soft pronunciation, assigned to the seven classical planets and to seven pairs of opposites; and twelve 'simple' letters assigned to the twelve signs of the zodiac and the twelve months. As a mother letter Aleph governs Air, the breath that mediates between the fire of heaven and the water of earth, and it is associated with the chest and the act of breathing and with the temperate season.
A separate and much later system, the Hermetic Order of the Golden Dawn (founded 1888), mapped the twenty-two letters onto the twenty-two trumps of the tarot along the paths of the Kabbalistic Tree of Life. This tarot correspondence is a modern Western-esoteric overlay, not part of the ancient Hebrew or classical Kabbalistic tradition. In that Golden Dawn scheme Aleph is assigned to The Fool (trump 0) on the eleventh path.