General:
* Quotes: This is a common and widely understood synonym.
* Speech marks: This is a more formal synonym, particularly used in British English.
* Double quotes: This specifically refers to the most common type of quotation mark, but it doesn't encompass single quotes.
Specific:
* Single quotes: If you are referring specifically to the single quotation mark, use this term.
* Apostrophes: Although they are used differently, apostrophes are visually similar to single quotation marks and sometimes mistakenly called that.
Figurative:
* "Scare quotes": This informal term refers to quotation marks used to distance oneself from the enclosed word or phrase, implying skepticism or irony.
Ultimately, the best alternative depends on the specific situation and the level of formality desired.