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: Webster's Revised Unabridged Dictionary (1913)