Bible dictionaries
Jasher
What Bible dictionaries say about “Jasher”, one article after the other.
Easton’s Bible Dictionary & Webster’s 1828 Dictionary
Jasher - (Easton's Bible Dictionary)
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).
Matthew George Easton, Easton’s Bible Dictionary; Noah Webster, American Dictionary of the English Language (1828)
The article in Easton + Webster 1828Smith’s Bible Dictionary
William Smith; revised by F. N. Peloubet and M. A. Peloubet; CrossWire SWORD module Smith 1.3
The article in Smith