What is "azmon"

Azmon ( or ; ) is an unidentified site, marking the western portion of the southern frontier of Judah before the point where "it went out at the Brook of Egypt". It is mentioned in the Hebrew Bible books of Numbers and Joshua .

Azmon lends itself to a common meter hymn tune. A number of Christian hymns, most notably O For a Thousand Tongues to Sing, have been set to that tune.