Source : Webster's Revised Unabridged Dictionary (1913)

Seventy \Sev"en*ty\, n.; pl. {Seventies}.
   1. The sum of seven times ten; seventy units or objects.

   2. A symbol representing seventy units, as 70, or lxx.

   {The Seventy}, the translators of the Greek version of the
      Old Testament called the Septuagint. See {Septuagint}.

Source : WordNet®

seventies
     n 1: the decade from 1970 to 1979 [syn: {1970s}]
     2: the time of life between 70 and 80 [syn: {mid-seventies}]