By Mary Morel
Reader’s question: How do you use hyphens with ages, for example, two year old child?
Answer: We hyphenate words that act as a unit to describe the word that follows.
Two year old describes the age of the child, so you would write two-year-old child.
This rule applies generally with hyphens, for example, long-term plan, five-storey building.
If the words are not modifying the following word, we don’t hyphenate them. For example, in the long term, the building has five storeys.
Hyphens become a bit more complicated because we often hyphenate words that are commonly used together, for example, bitter-sweet.
Read my blog on hyphens.
Read the Chicago Manual of Style Online hyphenation table.
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