position 12 in a countable series of things
"She finished her marathon as the twelfth runner to cross the finish line."
one part in twelve equal parts
"The recipe calls for a twelfth of a cup of honey, which is just enough to sweeten the tea without making it too sticky."
One of twelve equal parts of a whole.
"The clock chimes for the twelfth time, marking exactly one hour on the face."
The ordinal form of the number twelve, describing a person or thing in position number 12 of a sequence.
"After waiting through eleven long hours, she finally reached her twelfth stop on the tour bus route."
The word "twelfth" comes from Middle English and Old English, where it meant the ordinal number following twelve. It is formed by adding a suffix meaning "-th" to the base word for twelve.