Time for some close reading. It has long been customary to use an apostrophe to indicate omission of a letter, as in “don’t” or “ma’am” A single apostrophe is sometimes used to stand for multiple omitted letters, as in ‘em for them. /1 On rare occasions, multiple apostrophes are used, as in fo'c's'le, from the nautical term forecastle and sha’n’t for shall not, common from the late 18th century to early 20th; the only current example I can think of is “rock ‘n’ roll.” /2