From William Shakespeare’s MACBETH

The sisters are called "witches" only once in the play—but they're called "weird" six times.

The word "weird" comes from the Old English term “WYRD," meaning "fate.“

This could indicate the witches are in some way associated with the three fates of classical mythology.

Since the "fates" are supposed to control man's destiny, calling them "weird" just might suggest that Macbeth does not have any control over his actions, and that his choices are not really his to make.

Weird Sisters vs. Witches

Weird Old English wyrd (n.) "fate, destiny," literally "that which comes," from Proto-Germanic *wurthis (cf. Old Saxon wurd, Old High German wurt "fate," Old Norse urðr "fate, one of the three Norns"), from PIE *wert- "to turn, wind," (cf. German werden, Old English weorðan "to become"), from root *wer- (3) "to turn, bend"

The modern sense of weird developed from Middle English use of weird sisters for the three fates or Norns (in Germanic mythology), the goddesses who controlled human destiny. They were portrayed as odd or frightening in appearance, as in "Macbeth," which led to the adjectival meaning "odd-looking, uncanny," first recorded 1815.

Weird

The Fates have the subtle but awesome power of deciding a man's destiny. They assign a man to good or evil. Their most obvious choice is choosing how long a man lives. There are three Fates:

Clotho, the spinner, who spins the thread of life.

Lachesis, the measurer, who choses the lot in life one will have and measures off how long it is to be.

Atropos, she who cannot be turned, who at death with her shears cuts the thread of life.

The Fates from Greek Mythology

The Fates are old and predate the gods. It is not entirely clear how far their power extends. It is possible that they determine the fate of the gods as well. In any case, not even the most powerful is willing to trifle with them.

Fates - Continued

https://www.youtube.com/watch?v=MzTYLWArvjY

Shakespeare's principal source for the Three Witches is found in the account of King Duncan in Raphael Holinshed's history of Britain, The Chronicles of England, Scotland, and Ireland (1587). In Holinshed, the future King Macbeth of Scotland and his companion Banquo encounter "three women in strange and wild apparel, resembling creatures of elder world" who hail the men with glowing prophecies and then vanish "immediately out of their sight." Holinshed observes that "the common opinion was that these women were either the Weird Sisters, that is… the goddesses of destiny, or else some nymphs or fairies endued with knowledge of prophecy.

Background

The Three Witches represent darkness, chaos, and conflict, while their role is as agents and witnesses. Their presence communicates treason and impending doom. During Shakespeare's day, witches were seen as worse than rebels, "the most notorious traitor and rebel that can be." They were not only political traitors, but also spiritual traitors as well. Much of the confusion that springs from them comes from their ability to straddle the play's borders between reality and the supernatural. They are so deeply entrenched in both worlds that it is unclear whether they control fate, or whether they are merely its agents. They defy logic, not being subject to the rules of the real world.

Analysis

The witches' lines in the first act: "Fair is foul, and foul is fair: Hover through the fog and filthy air" are often said to set the tone for the remainder of the play by establishing a sense of moral confusion. Indeed, the play is filled with situations in which evil is depicted as good, while good is rendered evil. The line "Double, double toil and trouble" communicates the witches' intent clearly: they seek only to increase trouble for the mortals around them.

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