Definition of "threescore"

And their brethren, heads of the house of their fathers, a thousand, and seuen hundred and threescore, very able men for the worke of the seruice of the house of God.

1611, The Holy Bible, […] (King James Version), London: […] Robert Barker, […], 1 Chronicles 9:13

Words cannot picture her; but all men know / That solemn sketch the pure sad artist wrought / Three centuries and threescore years ago

1874, James Thomson, The City of Dreadful Night, XXI

We live our lives in three dimensions for our threescore and ten allotted years. Yet every branch of contemporary science, from statistics to cosmology, alludes to processes that operate on scales outside of human experience: the millisecond and the nanometer, the eon and the light-year.

2012 January, Robert L. Dorit, “Rereading Darwin”, in American Scientist‎, volume 100, number 1, archived from the original on 14 November 2012, page 23