The Chicago Manual of Style, sixteenth edition (2010) uses the rather odd phrase "word used as [a] word" to describe such instances:
7.58 Words and phrases used as words. When a word or term is not used functionally but is referred to as the word or term itself, it is either italicized or enclosed on quotation marks.
The Associated Press Stylebook (2002) uses the similar phrase "words as words":
words as words The meaning of this phrase, which appears occasionally in this book and similar manuals that deal with words, is best illustrated by an example: In this sentence, woman appears solely as a word rather than as the means of representing the concept normally associated with the word.
In mainstream U.S. publishing, "word used as [a] word" has become the standard way to refer to usage of this type.