(Hebrew for Kingdom) The "fallen sephirah." Malkuth is the Physical World or the Physical Body.

"The physical world is the valley of bitterness, the kingdom of Malkuth, the kingdom of Samsara. The Wheel of Samsara incessantly turns and the ego comes and goes; it disincarnates and returns always suffering, always searching without finding. The Tenth Arcanum, the Wheel of Retribution, is terrible, and the whole world is a slave of this fatal Wheel of the Centuries. Whosoever wants to be liberated from the fatal Wheel of Samsara must dissolve the “I” and incarnate the Soul. This labor is very difficult and those who achieve it are very rare. Really, the kingdom of Malkuth is a terrible filter. The refuse of this filter is what is common and current, which is swallowed by the Abyss. The gold, the select, the true Human Being, the Angel, is the conception, and the struggle is indeed difficult. Nature is implacable and the birth of an Angel-Human Being costs thousands, or better said, millions of victims. 'Many are called and few are chosen.'” - from Tarot and Kabbalah