“Think that all women are witches, in the sense that a witch is a magical being.”

Source: Drawing Down the Moon: Witches, Druids, Goddess-Worshippers, and Other Pagans in America

The Marvelous Land of Oz (1904), Ch. 1 : Tip Manufactures Pumpkinhead
Later Oz novels

Source: The Wee Free Men

As quoted in Womanspirit Rising: A Feminist Reader in Religion (1979) by Carol P. Christ and Judith Plaskow
Context: I am a witch, by which I mean that I am somebody who believes that the earth is sacred, and that women and women's bodies are one expression of that sacred being. My spirituality has always been linked to my feminism. Feminism is about challenging unequal power structures. So, it also means challenging inequalities in race, class, sexual preference. What we need to be doing is not just changing who holds power, but changing the way we conceive of power. There is the power we're all familiar with — power over. But there is another kind of power — power from within. For a woman, it is the power to be fertile either in terms of having babies or writing books or dancing or baking bread or being a great organizer. It is the kind of power that doesn't depend on depriving someone else.

"The Witchcraft of Mary-Marie", in Baum's American Fairy Tales (1908)
Short stories
Context: "But what can I do?" cried she, spreading out her arms helplessly. "I can not hew down trees, as my father used; and in all this end of the king's domain there is nothing else to be done. For there are so many shepherds that no more are needed, and so many tillers of the soil that no more can find employment. Ah, I have tried; hut no one wants a weak girl like me."
"Why don't you become a witch?" asked the man.
"Me!" gasped Mary-Marie, amazed. "A witch!"
"Why not?” he inquired, as if surprised.
"Well," said the girl, laughing. "I'm not old enough. Witches, you know, are withered dried-up old hags."
"Oh, not at all!" returned the stranger.
"And they sell their souls to Satan, in return for a knowledge of witchcraft," continued Mary-Marie more seriously.
"Stuff and nonsense!" cried the stranger angrily.
“And all the enjoyment they get in life is riding broomsticks through the air on dark nights," declared the girl.
"Well, well, well!" said the old man in an astonished tone. "One might think you knew all about witches, to hear you chatter. But your words prove you to be very ignorant of the subject. You may find good people and bad people in the world; and so, I suppose, you may find good witches and bad witches. But I must confess most of the witches I have known were very respectable, indeed, and famous for their kind actions."
"Oh. I'd like to be that kind of witch!" said Mary-Marie, clasping her hands earnestly.

Every Last Drop, Character: Joe Pitt (narration)
Joe Pitt Casebooks

The Lion, the Witch and the Wardrobe (1950) Ch. 15: Deeper Magic from Before the Dawn of Time
The Chronicles of Narnia (1950–1956)

The Wonderful Wizard of Oz (1900)
Context: There were only four witches in all the Land of Oz, and two of them, those who live in the North and the South, are good witches. I know this is true, for I am one of them myself, and cannot be mistaken. Those who dwelt in the East and the West were, indeed, wicked witches; but now that you have killed one of them, there is but one Wicked Witch in all the Land of Oz — the one who lives in the West.