Binah represents the female potency of the Universe as Chokmah represents the male, both will be better understood when watched in correlation with each other. The are the first manifestation of the principle of polarity, the opposites that are to be seen as a unity. Chokmah is the force and Binah the form, the receiving of Chokmahs power, its perception and understanding. Without Binah the unrestricted, formless power of Chokmah would be but an empty combustion in nowhere's land.
Binah is thus the Great Mother, the Great Sea, the archetypal womb from which all life comes into manifestation. But she also means restriction, binding and limitation - which is why she heads the Pillar of Severity and not that of Mercy which one might be attempted to view as more 'mother-like'.
Here we must understand that birth is the beginning of death. The unrestricted powers emanating from Kether are immortal and timeless, those emanating from Chokmah are undefined and not even born into any substanstial existance. Binah receives these unbinded forces and forms them into being. But as soon as being begins it is subjugated to time and age and ultimately death.
Binah is thus connected to Saturn, the Father of Time who in his Greek form of Kronos had the unpleasant habit of eating his children. Therefore Binah is not only the Bright Fertile Mother but also the Dark Sterile Mother, and the proverbial Terrible Mother who subjects her children to the merciless circle of birth and death, age and illness, rise and fall.
However, Binah is the will to form, the actual form takes place not in Binah but in Chesed. Like the element of Water which receives but leaves the actual birth to someone else Binahs children will only see the light of day on the other side of the Abyss.
Binah represents Neshamah of the soul, the World of Briah, where individual potentials and powers are identified and specificated. It combines perception, realization and understanding, the first initiation of consciousness.
In the Tarot Binah is associated with the Threes and the Queens. The Three is the number associated with the manifestation of matter with matter being just about anything that is manifest. The Queens are the Mothers of their elements and Suits.
See below the Tarot cards corresponding to Binah: