sic
Latin for “thus” — inserted in brackets inside a quotation to show that an error or oddity is the original author's, not yours.
“[sic]” goes immediately after the surprising word, inside the quotation: “the data was [sic] inconclusive.” It tells the reader you transcribed faithfully and noticed. Without it, a typo in a quotation reads as your typo.
Use it sparingly and never as a sneer. Where the error is trivial and irrelevant, many editors prefer a silent correction in square brackets, or paraphrasing to avoid the problem entirely. Italicising sic is optional and varies by style; the brackets are not.
See also
Direct quotationReproducing a source's exact words inside quotation marks or as a block, with a citation that includes a locator.Block quotationA long quotation set off from the body text as its own indented paragraph, without quotation marks.Ellipsis in quotationsThree spaced or unspaced dots showing that you have cut words out of the middle of a quotation.