\Sev"en*ti*eth\, a. [AS. hund-seofontigo[eth]a.]
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.

\Sev"en*ti*eth\, n.
1. One next in order after the sixty-ninth.
2. The quotient of a unit divided by seventy; one of seventy
   equal parts or fractions.