Symbolic Meaning of Number Thirteen

The symbolic meaning of number thirteen receives a shady interpretation in Norse myth, when an honorary banquet was held in Valhalla for Baldur (god of nobility, redemption and admirable strength) among other twelve Norse gods. Loki (the trickster) came to the banquet as the uninvited thirteenth guest. Afterwards, we learn Baldur was slain by Höðr who, to execute the god, was given a magic spear by Loki.
Similarly, the darker symbolism of thirteen continues in its Christian association with the Last Supper. Twelve disciples and the Christ, formed a group of thirteen to share the last meal. Here, thirteen is seen as a foreboding omen as we learn of Christ’s fate after the gathering.
In the same vein, Friday the thirteenth is commonly reviled as it was said the Last Supper in the upper room took place on a Friday. Further, Friday 13th in 1307 was the date on which the assembly of the Knights Templar were systematically assasinated.
In the guest company scenarios we can point to Judas or Loki as the thirteenth figures and so deem the association of the number thirteen as unlucky.
However, one may also consider the opposite, and recognize the enlightened guests,Christ and Baldur as the thirteenth entities. This brings about a heightened perception of the number and lends symbolism of:

• Ascension
• Resurrection
• Enlightenment

In ancient Greece Zeus was counted as the thirteenth, and most powerful god. Here the associations of Zeus give the number thirteen symbolic meanings such as:

• Totality
• Completion
• Power
• Realization
• Attainment

The symbolism of thirteen comes into play when we learn of Osiris (the Egyptian god of life, death and powerful solar symbol) was murdered by his brother Typhon. Isis, Osiris’ wife and sister collected his body with intent to restore Osiris back to life.
However, Typhon stole Osiris’ body and cut it into fourteen pieces and scattered them about the earth. Isis continued her quest to revive her beloved, but could only reclaim thirteen of the fourteen body parts (the fourteenth part being Osiris’ penis which interestingly fell into the Nile and was eaten by a school of fish which are also symbolic).
This tale symbolically implies that the meaning of number thirteen is the precursor to completion. 
Also in Egypt, there are thirteen steps upon the ladder that leads to eternity. Upon the thirteenth step it is said the soul reaches the source of itself and attains spiritual completion.
There are thirteen moons in a calendar year. As such, the symbolic meaning of number thirteen deals with moon associations such as:

• Femininity
• Magic
• Psyche
• Emotion

From a numerological perspective, we first recognize the presence of the three.Symbolic meaning of number three is vast and powerful. At its simples, the symbolic meaning of the number three deals with:

• Creation
• Completion
• Order
• Advancement
• Mystery

We then recognize the presence of the number one, which precedes the number three. This amplifies the preexisting symbolic meaning of the number one, which deals with:

• Beginnings
• Initiation
• Solidarity
• Unity
• Birth

Singly, these individual number meanings put together tell a story of a path that is just beginning (number one), and will lead to greatness in the expression of the union of opposites (number three).
Adding and reducing the single numbers, is a common practice in numerology. Do this, we receive another symbolic meaning of the number thirteen. To wit: 1+3=4. Fours lend a grounding effect to the high-pitch energy of 13. The energy of number four brings the thirteen down to a level where we can begin to rationalize its meaning more clearly. The reduction to four is a message that at its core, the thirteen is a means to an end and this numeric energy will always return us to the calm root or source which is ultimately our cosmic home.
In a deeper numerological perspective, thirteen can be considered the fulfillment or manifestation of the number three.
It is also important to note the number thirteen is a prime number and is only divisibly by itself. This is symbolic of:

• Incorruptible nature
• Purity
• Integrity

In the language of the Tarot, the number thirteen is represented in the Death card, which is symbolic of:

• Transition
• Change
• Inevitability

More on this topic can be found on the meaning of the thirteenth Tarot card page, as well as the meaning of number thirteen on my blog. 
I hope you have enjoyed these observations about the symbolic meaning of number thirteen.