Dreams in the Witch House, Chapter I : When Shall We Three Meet Again?

The Bard of Avon has called them the "Weyward Sisters, hand in hand, Posters of the Sea and Land". The name though did not seem to catch up and in most modern editions they have turned into the Weird Sisters, and with that name they set off on their glorious career. Of course the noble editor had no purpose of insulting the Three Sisters. When he was calling them Weird he merely had the Anglo-Saxon Wyrd in mind. The word comes from the Old Norse Urðr which corresponds to destiny or personal fate. Far more than just a word though it was loaded with great importance in the Saxon society. The word Weird was merely an alternate spelling. 
Still, quite a few years ago, a young boy, who had no idea of the word's old meaning found a wonderful ambiguity in the name of the Weird Sisters as he read their chant:

A cavern. In the middle, a Cauldron boiling. Thunder.

Enter the three WITCHES.

FIRST WITCH. 

Thrice the brinded cat hath mew’d.

SECOND WITCH. 

Thrice and once, the hedge-pig whin’d.
  THIRD WITCH. 

Harpier cries:—’tis time! ’tis time!
FIRST WITCH. 

Round about the caldron go;
In the poison’d entrails throw.—
Toad, that under cold stone,
Days and nights has thirty-one;
Swelter’d venom sleeping got,
Boil thou first i’ the charmed pot!
ALL. 

Double, double toil and trouble;
Fire burn, and caldron bubble.
SECOND WITCH. 

Fillet of a fenny snake,
In the caldron boil and bake;
Eye of newt, and toe of frog,
Wool of bat, and tongue of dog,
Adder’s fork, and blind-worm’s sting,
Lizard’s leg, and owlet’s wing,—
For a charm of powerful trouble,
Like a hell-broth boil and bubble.
ALL. 

Double, double toil and trouble;
Fire burn, and caldron bubble.
THIRD WITCH.

  Scale of dragon; tooth of wolf;
Witches’ mummy; maw and gulf
Of the ravin’d salt-sea shark;
Root of hemlock digg’d i the dark;
Liver of blaspheming Jew;
Gall of goat, and slips of yew
Sliver’d in the moon’s eclipse;
Nose of Turk, and Tartar’s lips;
Finger of birth-strangled babe
Ditch-deliver’d by a drab,—
Make the gruel thick and slab:
Add thereto a tiger’s chaudron,
For the ingrediants of our caldron.
ALL.

  Double, double toil and trouble;
Fire burn, and caldron bubble.
SECOND WITCH.

  Cool it with a baboon’s blood,
Then the charm is firm and good.

The young boy very reluctantly grew up and learned the meaning and history of the small word, but in his heart that marvelous ambiguity remained, and in his heart the Wyrd Sisters always remained Weird.
They mixed their stews and brewed their brews and spoke with Hecate, and were connected, at least indirectly, to the King's murder. Mystical stuff, no doubt, yet again, why weird? Who are they and what makes them so?
The Bard is very specific in telling us what the women were. The stage instructions before their acts are explicit "Enter three WITCHES". In no way can we suppose that Shakespeare might have attributed a different meaning to the word. Macbeth was written between 1603 and 1607, with the first performance probably taking place in 1611. That is right after the accession of King James to the English throne and his Act against Conjuration, Witchcraft and dealing with evil and wicked spirits, an extremely severe document that brought the penalty of death, without the benefit of clergy to anyone employing witchcraft, even for such harmless acts as locating lost treasure. In the Bard's time, therefore, there was no question about the nature of a witch and her agenda as the word carried the full weight of a legal terms. She was necessarily the sinister servant of the Devil, a betrayer of her king and country. A role maybe not unfit to the Three Sisters in Macbeth, who brought a whole kingdom into disarray.
Yet again the three Wyrd Sisters, not only named after Fate but working to reveal, or even forge, the fate of men, such as Macbeth, invoked across the whole of Europe memories of three beings of vastly greater power and age. In the north they were the Norns: Urðr, Verðandi, Skuld; in Greece they were the Moirae, Clotho (Nona in Latin), Lachesis (Decima) and Atropos (Morta); all over Europe, the names might change, but the people, even in those christian years knew who they were and still left gifts for them, in the cribs of the newborn.

They might be 'sisters' in the Immortal Bard's tale, yet things were soon about to change. In the beginning of the 20th century Jane Ellen Harrison, a British scholar, famous for her study of Greek mythology, points towards the existence of female trinities, such as the Fates and the Graces, and compares them to the three seasons of the ancient Greek year and the stages of a woman's life.
At that point the Three Witches stop being siblings. Their ages change to correspond with the stages of a woman's life as perceived in the classical societies. James Frazer, author of the Golden Bough, goes as far as to establish archetypes for two of the three deities,  giving them a blood relationship and identifying them with Demeter and Persephone.
The third former 'sister' though, still remained nameless, yet not for long. She finds her name and description in the novel Moonchild, by the British magician Aleister Crowley. In the novel, old Atropos, the Latin Morta (meaning Death) becomes Hecate, an ugly crone, filled with hate and envy.
The idea of the Triple Goddess appears most elaborately in the works of the poet Robert Graves, whose The White Goddess: a Historical Grammar of Poetic Myth, clearly defines, in 1948, the trio of a Maiden, a Mother and a Crone, corresponding to the waxing, full and waning moon respectivelly.
Thus three neatly defined mythical creatures where sketched: the Virgin, the Mother and the Crone. The definitions of the three words are pretty straight forward by modern standards, yet in their earlier context they should be perceived in a more loose and figurative manner. Thus their modern translation would be "the Hot Chick, Mom and that creepy Old Lady".
In one plain word, women. Well, not exactly. Not all of them at least, not your sister, the plain looking neighbor girl, or someone else's mother (unless she's hot, or a crone). Merely the ones that "mattered", which eventually tends to mean the intimidating ones.
The words are definitely loaded and equally important. Each of them represents a unique fictional creature with discreet characteristics, attributes and abilities, personified (separately for each one of us) by several living examples around us, but clearly defined in their pure form.
Here follows a short attempt at collecting the characteristics in a living specimen that would make it a typical anthropomorphic personification of the Three Witches:

" All these natures are combined in woman." -Moonchild, Aleister Crowley

A. The Virgin (aka The Hot Chick):
"Artemis is unassailable, a being fine and radiant;" -Moonchild, Aleister Crowley
In the early modern christian world sexuality was closely connected to sin, and virginity was akin to pureness. Despite the symbolic importance of virginity in lore and legend, it is obvious that the term Virgin was widely used to mean young woman in most contexts, as the notion of an non-virgin young girl was unheard of (though of course not nonexistent, just unheard of, since nobody would speak of it). Yet again, the obvious sexual undertones in the term clearly point to a specific category of young women. Those who would be welcome to evoke those undertones, the Hot Chicks.
There is nothing strange about the Hot Chick being the first member of the Coven. The Hot Chick has through the years been capable of supernatural feats.She can change a person's mood, make his depressed beyond hope of relief, worst of all, she can make people want her (in sinful ways too). Through the years people have communed with the Hot Chick in the same way they would have communed with a summoned demon.
To elaborate:
The Hot Chick has to be approached and treated with caution. A strategy has to be formed if she is to be dealt with. Much like in the case of a summoned demon, the right words have to be said in the right order, a slight mistake can lead to eternal damnation. Even if everything works right, things will only become scarier as you get to know her.

B. The Mother (aka 'Not now mom!')
"the woman in the fullness of life is the sublime Persephone, for whose sake Demeter cursed the fields that they brought forth no more corn, until Hades consented to restore her to earth for half the year." -Moonchild, Aleister Crowley
As with the term Virgin, Mother is a much wider term than it seems at first glance. In the same way that Virgin can mean any young girl, despite of her sexual activity, the Mother would represent any fully grown and mature woman. There are many, even modern, societies after all, where the destination of any mature woman is motherhood, one way or the other.
The Mother though, is one of those figures that have to be your own in order for their full supernatural potential to be unleashed. In a person's younger years the mother is usually a figure with supernatural powers anyways. There are always some things she can magically do or undo, rituals that have to be performed before the youngster can go to bed, or leave for school, and she has always a weird way of finding things out. 
The Mother must be treated with ritualistic caution, even by the adult offspring. In the younger years there are things that must be hidden from her, since she represents the law in some way, and in contrast there are things that can only be said to her, since telling them to anyone else would be embarrassing. When the years pass the rules change, but rules do exist. The mother will make her ritualistic remarks and the specified ritual answers must be chanted in response.

C. The Crone (aka The Other One)
"Hecate is the crone, the woman past all hope of motherhood, her soul black with envy and hatred of happier mortals;" -Moonchild, Aleister Crowley
In contrast to the previous two members the Crone got all the bad publicity. Virgin after all meant pure (and of course she was hot) and the Mother was someone's mom. Even the name of the Crone was an insulting term. The word entered the written Middle English in 1386 in the works of Chaucer, via the Middle Dutch word croonje or caroonje meaning 'carcass' literally and 'old ewe', figurativelly, stemming in turn from the Old Northern French caroigne, meaning 'carrion' with a possible figurative meaning of  'wrinkled old woman'.
Among the Coven the Crone has proven to have the most persistent impact. Most of her bad publicity comes from the fact that in most children's tales the witch had to be a Crone. The Hot Chick, for one, is not at all appropriate for children, and the Mother is mommy (and probably too early for her to be demystified). Combine that with the obvious fear and ugliness of old age and death and the picture is almost complete.
A less obvious characteristic about the old ladies I have met in rural territories is their pragmatism. They have finally grown into persons who know what they want exactly, and will not hesitate to demand it from the younger, who after all owe them so much.
In contrast with the other two, there is no way in which the crone should be addressed. In fact she should not be addressed at all if possible. Many warlocks have summoned demons, but nobody was stupid enough to write a book about summoning Lucifer.
The fact that people perform their everyday tasks in simpler and more effective ways through the generations, grants to the Crone one more mystic power: her Knowledge of the Old Ways, which is gradually getting lost (most of the times for very good reasons).


What makes all three most intimidating though is the fact that we need to deal with them. A man's childhood fear of ghosts and ghouls will eventually die away, in a sane person at least, as he realizes that time passes and yet he has not encountered any. The same cannot be said about the Virgin, the Mother and the Crone. In all our lives, even after the elves, the fairies and the undead are gone, the Three Witches will be the only enduring, constantly present fairytale creatures in our lives.