Kali Symbolism

She is called indescribable. The mystery of Great Goddess Kālī may be impossible to describe or imagine. Any form cannot contain all depth of its sense. It is difficult to explain her symbolism rationally. Various Shakta Hindu cosmologies, as well as Shakta Tantric beliefs, worship Her as the ultimate reality or Brahman. Ramprasad concedes that ordinary mortals could be bedazzled by these stark truths. It is to not be found by a conventional appraisal of Her physical appearance. But in same time, Her form is a meditative symbol, useful for realizing the nature of reality. The symbol can be interpreted at different levels, from the highest to the gross. Besides, in our times of Kali Yuga, many symbolic aspects have been misinterpreted.  Therefore many are frightened by appearance without seeing the deeper meaning. But if you view Kālī through the metaphysical lens, then there is nothing that can terrified.
NAME

काळी

Name Kālī means "the black one" and is also derived from Sanskrit word kāla, which means black, the time as destroyer of all things. Kālī  is represented as the consort of Lord Shiva, on whose body she is often seen standing. Since Shiva is called Kāla or Mahakāla - the eternal Time, thus, Her name is the feminine form of name Kāla. Kālī, the Cause of Time or She Who is Beyond Time, activates Consciousness to perception, allows Consciousness to perceive.
TERRIBLE FORM
She is the Mother of all as well as the destroyer. Like a fearless warrior, alone amidst all, She is the queen of the battlefield, sword in hand, ghastly trophies all around her. The destructive aspect of Divine Shakti can release the Universe in general and us in particular from the clutches of the evil. As the power of time, Kālī liberates through disintegration and the destruction of illusion. This destructive power clears the way for new life. She destroys ignorance in order to bestow knowledge. Kālī embodies all fear and yet is beyond it. After encountering Her there is nothing to clinging through fear.
COMPLEXION
She is black, or deep blue, the color of deepest Night. The blackness of Kālī represents the unknown before creation, when nothing material existed. This primordial state was dark. As is Kālī, as is the womb, dark and mysterious. Black is not a color, but the absence of color. As says the Mahanirvana Tantra: "Just as all colors disappear in black, so all names and forms disappear in her". Her dark color is the ultimate reality in which all distinctions disappear.
NUDITY
The Devi is naked, as is Shiva, for like Him, She is clothed with space, digambari. She is infinite, and no finite dress can cover Her. In Her primordial nakedness, Kālī is free from the illusory covering, from all maya, all conditional existence and false consciousness.
3 EYES
Kālī sees every moment through the third eye, the eye of non-dual Wisdom. The Mahanirvana Tantra says: "As She surveys the entire universe, which is the product of time, with Her three eyes - the Moon, Sun, and Fire - therefore She is endowed with three eyes." There are some explanations of three eyes:
the Moon, Sun, and Fire or the Ichchha, Kriya, Jnana;
three gunas: She creates with Her sattva guna (quality of goodness and purity),
preserves with rajas (passion and activity),
and destroys with tamas (ignorance and inertia);
and the three modes of time: past, present, and future.
BLOOD TONGUE 
Oh, the delightful outstretched tongue of Kālī distinguishes her from all other gods and goddesses of the Hindu pantheon. In Devi Mahatmya, Kālī unfurls her tongue in her role as the ultimate deliverer called upon to salvage a situation that seems hopelessly out of control. She is summoned by Durga herself to destroy the demon Rakta-bija, whose name means blood-seed. Blood represents life physically and spiritually. On one level it represent the overwhelming power of desire, thirst of life and reproduction. Ultimately the entire earth has been filled with these seeds. This is why She shows Her red tongue - in order to make all existence free.

The blood indicates (the red) Rajas Guna, Divine rajas. Her white teeth indicative of Rajas suppress by Sattva. Certainly, blood has a sacred and sacrificial meaning in every religion and culture as the symbol of the divine life manifested on the lower planes or the lower nature, and, at same time, a symbol of the cleansing of one's own lower mind to the higher consciousness.
FULL BREAST
The physical characteristics of the Devi in swelling breasts and hips are emblematic of Her great Motherhood. She is the nourisher of all beings. The milk of these is the food with which She nourishes the world and the drink of immortality with which She liberates us.
NECKLACE OF SKULLS
She is Shabdabrahman, the source of creation. So, the fifty skulls represent the fifty letters of the Sanskrit alphabet, the origin of sound, all mantras, all universe.
Also Her garland bespeaks death in life and life in death – each embodying and following the other in endless cycles. The severed heads can represent slain human egos that have sought to usurp the Divine Mind. She blesses devotees by cutting us free from the cycle of karma and takes a garland of the physical manifestations to Herself.
THE SKIRT
The amputated hands which are strung together to form this garment represent for her devotees the ultimate act of devotion. Our hands are the instruments through which we carry out our karma, believing ourselves to be the masters of our own destinies. The goddess allows no such misconception, as she is the giver of life and also its terminator. All human actions and their results go to the Divine Mother. It is in Her that all acts originate and it is into Her that they finally dissolve.
HANDS
Kālī's four arms represent the complete circle of creation and destruction.
Two right arms: The upper right arm grants fearlessness, and the lower right arm offers boons. She protects Her children from danger, and She fulfills their desires.The right upper hand makes the gesture of dispelling fear, or the gesture of assurance of safety (abhayamudra)

and the right lower hand makes the gesture of granting boons (varamudra).

Two left arms: She holds a sword with the upper left arm and a severed head with the lower. Sword symbolizes the wisdom, knowledge or ability to cut through delusion or obstacles and annihilates all and anything that is not worthy of keeping.

Holding the sword of  knowledge, She slices our fragile, false self-images away and can cut human bondage. So, this human head of sadhaka is free of attachment.

Often, the two left hands hold a severed head and cranial bowl of flames. The flames symbolize the cremation fire, which is the sacrificial fire that demands the ultimate sacrifice, namely that of our own mortal bodies.
SHIVA IS UNDER HER FEET
The Devi is in the position of Shavahridi, that is, on the breast of Shiva, in her union with Her consort, because She is the active, creative Prakriti, stimulated into manifest condition by the presence of Purusha. He is impersonal unmoving and inactive in actual dispensation. But Shakti, remaining in the center of the all-pervading Brahman, causes the cosmic creation. No creation is possible without their union. Together they make the cosmic Love that is the universal Way.

Two corpses are sometimes pictured, the lower being the eternally quiescent Shiva, and the upper being the Shiva united with Shakti in creation. Shiva is Nirguna and becomes Saguna, by coming in contact with Shakti. The feminine principle creates the cosmos in combination with the masculine principle. Shiva and Shakti are always together.

Kālī  appears to her believers as Shakti, that is as feminine energy in the form of a universal female divinity. And, after all, the contradictions at interpretation of Her image arise only in our limited mind while true nature is beyond conventional cause and effect, existence and duality. In Her omnipotence, Kālī includes all principles and Her image represent a power that transcends all this. Her abode is found in the act of transcendence, an enactment of the very power she supremely personifies. When She takes away the darkness of the outside world, She grants illumination of our inner world. Such is Her Grace.
Kālī symbolises Truth. And how it is possible to represent the Truth?

JAI MA KALI!