An erratum is one mistake in a printed book or paper that the publisher later points out. Once the pages are already printed, they cannot easily take the error back, so they add a short correction — sometimes a slip of paper, sometimes a note at the back. Strictly, erratum is one printed slip; the list of them is the Latin plural, errata, and that is the word you will see on the page headed “Errata”. It is a book-world word, used in academic books and journals more than in ordinary paperbacks. It is not a word for any old mistake in life — not a wrong text, not a wrong turn, not a wrong sum on a napkin.

勘誤。一處印錯叫勘誤；書後整份清單多半叫勘誤表，英文常用複數 errata。