Easton's Bible Dictionary (1897)
Slumber, a town in the mountains of Judah (Josh. 15:53).
Smith's Bible Dictionary (1863)
(slumber), a town of Judah in the mountain district, apparently not far from Hebron.
Hastings' Dictionary of the Bible (1898) & Schaff's Bible Dictionary
JA'NUM (slumber), a place in the tribe of Judah. Josh 15:53. The margin has "Janus" ("flight"). It was not far from Hebron, and Conder proposes to identify it with Beni Naim.
Hitchcock's Bible Names (1869)
sleeping