Hyphens, En Dashes, Em Dashes
Q. Dear Chicago, I’m in a debate with my 73-year-old publisher. I lost my AP Style book in a recent move and I can’t remember the rule for putting hyphens in a person’s age. My publisher says it is only used when the age is a modifier. I say it needs to be used when it is a noun as well, such as: “The healthy 18-year-old jumped in his car . . .” He claims it is only used in a sentence similar to this: “An 8-year-old boy.” Please let me know which is correct so I can end this debate and put this magazine to bed! Thank you, Missouri.
A. Dear Missouri: You are correct. In a phrase such as “a five-year-old,” the age modifies an implicit noun. That the hyphens are necessary whether a noun is stated or implied was not made explicit in the fourteenth edition of The Chicago Manual of Style. The fifteenth edition clarifies things:
age terms: a three-year-old, a five-year-old child, a fifty-five-year-old woman, eight- to ten-year-olds. (Hyphenated in both noun and adjective forms.)
