noun the next in order after the eleventh.
2. twelfth ·noun an interval comprising an octave and a fifth.
3. twelfth ·adj consisting, or being one of, twelve equal parts into which anything is divided.
4. twelfth ·noun the quotient of a unit divided by twelve; one of twelve equal parts of one whole.
5. twelfth ·adj next in order after the eleventh; coming after eleven others;
the ordinal of twelve.