What is madhkur?

Some articles on madhkur, madhkurs:

Bani Utbah's Victory Over Nasr Al-Madhkur At Zubarah in 1782
... war broke out between the Zubarah-based Bani Utbah tribe and the Al-Madhkurs ... the Bani Utbah tribe and the army of Nasr Al-Madhkur ... In 1783, Nasr Al-Madhkur lost the islands of Bahrain to the Bani Utbah tribe ...