Literary devices give words meaning or force beyond their literal meanings. Alcott uses many literary devices in Little Women.
One literary device she employs is malapropism, which is having a character use a wrong word that sounds like the correct word in order to create a comic effect. Amy, the youngest, often uses malapropisms to try to sound more grown up. In chapter one, she complains that the girls in her school "label," or say bad things, about her father. She means "libel." (Actually, the correct term would be slander, since the insults are spoken, not written, but that's not important.) Jo says,
If you mean libel, I’d say so, and not talk about labels, as if Papa was a pickle bottle . . .
Jo uses simile in the quote above, which is comparing two unlike things using the words "like" or "as." She does this when she compares their father to a pickle bottle. She also uses alliteration, which is putting two words that begin with the same letter in close proximity, when she says "Papa" and "pickle bottle."
Part of Alcott's genius is in her ability to use literary devices to characterize the March sisters. It is typical of Amy, who always wants to look good and rise in social status, to use malapropisms, just as it is typical for the talented wordsmith Jo to use similes and alliteration.