1) Diamond 2) Fraction of a minute 3) One part in sixty equal parts 4) Ordinal 
• (a.) Next in order after the fifty-ninth. • (n.) The quotient of a unit divided by sixty; one of sixty equal parts forming a whole. • (n.) The next in order after the fifty-ninth; the tenth after the fiftieth. • (a.) Constituting or being one one of sixty equal parts into which anything is divided.Sixtieth: words in the defini...
Six'ti·eth adjective [ As. sixtiogoða , sixtigoða .] 1. Next in order after the fifty-ninth. 2. Constituting or being one one of sixty equal parts into which anything is divided. Six'ti·eth noun 1. The quotient of a unit divided by sixty; one of sixty equal parts forming a whole. 2. The next in order after the fifty-ninth; the tenth after the fiftieth. 
[adj] - the ordinal number of sixty in counting order 2. [n] - position 60 in a countable series of things
60th adjective the ordinal number of sixty in counting order