- UK [sʌmθɪŋ] / US
used with numbers such as twenty, forty, sixty etc to refer to the age of someone who is between 20 and 29, 40 and 49 etc, or to make nouns meaning someone who is that age
I don't know how old Tom is – I suppose he must be forty-something.
a chat room for thirty-somethings
English dictionary. 2014.