Definition

1. Adjective:
   • Being one year of age: Describes a person, animal, or thing that has reached an age of exactly one year.

Usage

• The adjective "one-year-old" is used to specify the age of a subject. It is typically placed before a noun (e.g., a one-year-old child) or used as a predicate adjective (e.g., The child is one-year-old). Note the use of hyphens when the term precedes a noun.

Examples

• Adjective:
  • We are celebrating our one-year-old daughter's birthday.
  • The veterinarian examined the one-year-old puppy.
  • This cheese is a one-year-old Gouda.
  • How do you care for a one-year-old? (Here, "one-year-old" functions as a noun, meaning a one-year-old child or animal).

Advanced Usage

• Used as a nominalized adjective: When "one-year-old" is used without a following noun, it functions as a noun phrase referring to a person or animal of that age.
  • The one-year-old is learning to walk.
• In compound age descriptions: Can be part of a list or range.
  • The program is for one-year-old and two-year-old children.

Variants and Related Words

• Year-old (suffix): Used in combination with numbers to form adjectives indicating age (e.g., , ).
• Aged one year: A more formal synonym.
• 12-month-old: A less common, more precise synonym.

Synonyms

• Aged one: (Formal)
• Twelve-month-old: (Technical/Precise)

Related Phrases

• To turn one: The action of reaching one year of age.
  • My son will turn one next week.
• First birthday: The celebration of being one-year-old.
  • We're planning her first birthday party.

Adjective

1. one year of age