Green’s Dictionary of Slang

also, the n.

(US Und.) an arrangement with the authorities that, usu. through bribery, allows a criminal gang to operate in a specific town or area.

Goldin et. al. DAUL 18/1: Also (frequently followed by the preposition ‘in’). 1. A setup, often including bribery, under which a gang may operate in a specific area with immunity; the area itself. ‘We got the alzo in here. Ain't another cannon-mob (pickpocket gang) can hustle (steal in) this tip (crowd).’ 2. Arrangements necessary for the domination of a racket, or for the operation of an illegal establishment in a specific area. ‘Guinea Mike's got every nautch-joint (brothel) in town tied up with the alzo in.’ 3. The advantage gained over rivals through bribery or political connections. ‘No bangin' (shooting) needed. We got the alzo on Lefty's mob. The bulls (police) will have them all vagged (committed to jail for vagrancy) in a week.’.

In compounds

(n.)

(US Und.) a lucrative area for theft.

Goldin et. al. DAUL 18/1: Also [...] 4. A lucrative area for theft. ‘Wait'll we hit them two-stemmers (big towns) around Seattle. We'll glom onto (steal) plenty in them alzos.’.