Year-Old-Years-Old | Commonly Confused Words

Year-old

/jɪər əʊld/

Used to describe someone or something's age in terms of years

My grandfather is a wise eighty-year-old.The nine-year-old impressed everyone with her talent.He adopted a three-year-old beagle at the shelter.

This word has no antonyms

/jɪrz oʊld/

Used to indicate the age of someone or something, showing the number of years they have existed.

She will turn eighteen years old next month.Puppies typically reach maturity at one year old.The ancient tree in the park is over 200 years old.

Use hyphenation to connect words that function together as a single adjective before a noun.
Year-old is used with a specific number to describe age; it's a compound adjective.
Years old is used after a noun and doesn't require a hyphen.