What is "mawla"

Mawlā , plural mawālī is a polysemous Arabic word, whose meaning varied in different periods and contexts. In the Quran and hadith it is used in two senses: Lord; and guardian, trustee, helper. In the pre-Islamic era the term originally applied to any form of tribal association. During the early Islamic era, this institution was adapted to incorporate new converts to Islam into the Arab-Muslim society and the word mawali gained currency as an appellation for non-Arab Muslims.