The eleventh path is the first of the twenty two, and its numbering is the clearest single lesson in how the Tree is counted. The ten Sephiroth are paths one to ten in the older reckoning, so the connecting lines begin at eleven, and every path number in the atlas is offset from its letter's position by ten. Aleph is the first Hebrew letter and the eleventh path.
It joins Kether, the Crown, to Chokmah, Wisdom, running along the top of the Pillar of Mercy. In the diagram this is the shortest possible distance from the undifferentiated point to the first thing that can be called anything at all, and the tradition treats it accordingly: the path of the first distinction, where unity becomes a unity and something else.
Its letter is Aleph, one of the three Mother letters of the Sefer Yetzirah, and its element is Air. Aleph is written but not sounded, a silent letter that carries whatever vowel is placed with it, and the commentators make a great deal of that. A path from the Crown could hardly be assigned a letter with a noise of its own. The name of the letter means ox, and the older pictographic form is an ox head, which is why the path also collects associations of the yoked strength that pulls a thing into motion.
The tarot trump attached to it is The Fool, unnumbered or numbered zero, and that attribution is much later than the rest. The atlas treats the tarot overlay separately, because the correspondence between the trumps and the paths dates from the eighteenth century and after, while the letters and the Sephiroth do not.