1) Ordinal 
• (a.) Next in order after the sixty-ninth; as, a man in the seventieth year of his age. • (a.) Constituting or being one of seventy equal parts. • (n.) The quotient of a unit divided by seventy; one of seventy equal parts or fractions. • (n.) One next in order after the sixty-ninth.
Sev'en·ti·eth adjective [ Anglo-Saxon hund- seofontigoða .] 1. Next in order after the sixty-ninth; as, a man in the seventieth year of his age. 2. Constituting or being one of seventy equal parts. 
[adj] - the ordinal number of seventy in counting order 2. [n] - position 70 in a countable series of things
70th adjective the ordinal number of seventy in counting order