1) Being one of 12 equal parts 2) Electoral Amendment 3) Highest grade 4) Important February date 5) Last grade in high school 6) Last of a dozen 7) Like l, alphabetically 8) Next after the eleventh 9) One of a dozen 10) Ordinal 
Twelfth can mean: In mathematics: ==Music== ...
• (n.) The next in order after the eleventh. • (n.) The quotient of a unit divided by twelve; one of twelve equal parts of one whole. • (a.) Next in order after the eleventh; coming after eleven others; -- the ordinal of twelve. • (a.) Consisting, or being one of, twelve equal parts into which anything is divided. • (n.) An...
In music a twelfth is an interval comprising an octave and a fifth.
[adj] - coming next after the eleventh and just before the thirteenth in position 2. [n] - position 12 in a countable series of things
12th adjective coming next after the eleventh and just before the thirteenth in position
next after the eleventh; being the ordinal number for 12. · being one of 12 equal parts.