either of a pair of punctuation marks (“ … ”) used to enclose a direct quotation, or of single marks (ʼ … ’) for enclosing a quotation within a quotation
See quotation mark in American Heritage Dictionary 4
noun
Either of a pair of punctuation marks used primarily to mark the beginning and end of a passage attributed to another and repeated word for word, but also to indicate meanings or glosses and to indicate the unusual or dubious status of a word. They appear in the form of double quotation marks (“ ”) and single quotation marks (‘ ’). Single quotation marks are usually reserved for setting off a quotation within another quotation.