Sentence:  In his teens O ' Banion was <WSD>enrolled</WSD> in the vicious Market Street gang and he became a singing waiter in McGovern's Cafe , a notoriously low and rowdy dive in North Clark Street , where befuddled customers were methodically looted of their money by the singing waiters before being thrown out . 
Meaning of the word marked with <WSD> tags:  register formally as a participant or member