Immediately cognate with
Tatarбердәм(berdäm),
Uzbekbirdam(“united, unified”).
This term with this meaning appears to be a back-formation from Bashkir берҙәмлек(berðämlek) (compare Tatar бердәмлек(berdämlek), Uzbek birdamlik,
Uyghur بىردەملىك(birdemlik, “unity, unanimity”)), all of which which succeed to Chagataibirdamliq(“unity, unanimity”), which, in turn, was coined from Turkic bir "one" + Persian دم(dam, “moment”) + Turkic noun affix -lik.
Note Uyghur بىردەم(birdem, “now... now...; instantly”)), which has the same etymology, also succeeds to the Chagatai form, and appears to have preserved the original meaning; so it was not affected by the above lexical re-thinking due to back-formation.