seventy

noun, plural sev·en·ties.

1. a cardinal number, 10 times 7.
2. a symbol for this number, as 70 or LXX.
3. a set of this many persons or things.
4. seventies, the numbers, years, degrees, or the like from 70 through 79, as in referring to numbered streets, indicating the years of a lifetime or of a century, or referring to degrees of temperature: They live in the Seventies. His uncle is in his early seventies. It was in the seventies yesterday.
5. the Seventy, the body of scholars who produced the Septuagint.

adjective

6. amounting to 70 in number.

noun plural -ties

1. the cardinal number that is the product of ten and sevenSee also number (def. 1)
2. a numeral, 70, LXX, etc, representing this number
3. (plural) the numbers 70–79, esp the 70th to the 79th year of a person’s life or of a particular century
4. the amount or quantity that is seven times as big as ten
5. something represented by, representing, or consisting of 70 units

determiner

6. 1. amounting to seventythe seventy varieties of fabric
   2. (as pronoun)to invite seventy to the wedding

Old English (hund)seofontig, from seofon (see seven) + -tig (see -ty (1)). Cf. Old Frisian soventich, Middle Dutch seventich, Old Norse sjau tiger.