Next in order after the eleventh; coming after eleven others; -- the ordinal of twelve.

Constituting, or being one of, twelve equal parts into which anything is divided.

The quotient of a unit divided by twelve; one of twelve equal parts of one whole.

Even if you omit the [f] in your pronunciation of this word (which you shouldn"t do), it is retained in the spelling.

position 12 in a countable series of things

An interval comprising an octave and a fifth.