What is "juhaynah"

Juhaynah (;also transiterated as Djuhaynah or Johaynah) is a nomad tribe of the Arabian Peninsula and the largest clan of Banu Quda'a. Juhaynah are one of the most powerful Arabian tribes that rule important parts of the Hijaz. The Almarwani clan of the Juhaynah tribes are the leaders of the tribe. Almarwani clan are still live in the Arabian Peninsula, Saudi Arabia mostly in the city of Umluj or Omluj.