[Language: Old English; Origin: twelf]
the number 12 ⇨ dozen:
He received a twelve-month jail sentence.
Come at twelve (=12 o'clock).
Their son Dylan is twelve (=12 years old).
—twelfth adjective, pronoun:
her twelfth birthday
in the twelfth century
I’m planning to leave on the twelfth (=the 12th day of the month).