'Jasher' definitions:

Definition of 'Jasher'

Jasher upright. "The Book of Jasher," rendered in the LXX. "the Book of the Upright One," by the Vulgate "the Book of Just Ones," was probably a kind of national sacred song-book, a collection of songs in praise of the heroes of Israel, a "book of golden deeds," a national anthology. We have only two specimens from the book, (1) the words of Joshua which he spake to the Lord at the crisis of the battle of Beth-horon (Josh. 10:12, 13); and (2) "the Song of the Bow," that beautiful and touching mournful elegy which David composed on the occasion of the death of Saul and Jonathan (2 Sam. 1:18-27).

Jasher, righteous; upright