Talking or writing about someone’s age
asking about age
used for asking someone their age or talking about their age: How old are you now, Peter? ♦ I’m not sure how old she is.
used for talking about the age someone is at a particular time: At what age did you start playing the piano? ♦ Decide what age you want to retire at.
saying how old someone is
be 2/10/40 etc.
the most usual way of saying how old someone is: I will be 45 on my next birthday. ♦ She was only nine when her father left.
be 2/3/4 months old
used for talking about babies or young children: Most children don’t start to walk until they are around 12 to 14 months old.
of 2/10/40 etc.
: A child of three is unlikely to show much interest in reading and writing. ♦ Shortly after turning 19, she became engaged to a man of 45.
used before a noun, or used as a noun: a 56-year-old man ♦ a lively 20-year-old
under 2/10/40 etc.
less than a particular number of years old: Women under 40 generally don’t need regular mammograms. ♦ a preschool for the under-fives
over 2/10/40 etc.
more than a particular number of years old: You have to be over 65 to join.
when you are not saying exactly how old someone is
in your teens/twenties/thirties etc.
used for saying that someone is aged between 13–19, 20–29, 30–39, etc.: Children often become quite difficult in their teens. ♦ Police are looking for a man in his early thirties.
used as an adjective or noun for talking about someone aged between 20–29, 30–39, etc.: a successful twenty-something lawyer ♦ The program appeals to thirty-somethings.
aged between 13 and 19: a group of teenage girls waiting for the schoolbus
no longer young, but not yet old, usually used for someone aged between 40 and 60: a middle-aged couple with grown children