Green’s Dictionary of Slang

1. (Anglo-Ind.) a pipeful of tobacco; thus the pipe itself.

1832		M.H. Ali Observations Mussulmauns India II 180: This King [...] seeing the labourer had finished his second chillum (contents of a pipe) told him he had permission to depart, and desired him to take the hookha and keep it for his sake.
1844		J.W. Kaye Peregrine Pultuney II 114: He lounged about in his easy chair, smoked his chillum.
1855		W. Wilson Glossary 112/2: CHILAM, corruptly, CHILLUM, H. &c. [...] The part of the hukka which contains the tobacco and charcoal balls, whence it is sometimes loosely used for the pipe itself, or the act of smoking it.
1886		Yule & Burnell Hobson-Jobson (1996) 195: chillum, s. H. chilam; ‘the part of the hukka [...] which contains the tobacco and charcoal balls, whence it is sometimes loosely used for the pipe itself, or the act of smoking it’ (Wilson). It is also applied to the replenishment of the bowl, in the same way that a man asks for ‘another glass’.
1891		Civil & Milit. Gaz. (Lahore) 14 May 3/4: The only thing the sahibs don’t like about Indians is the hookah. If they smell the chillum, they get mad, and run out and say, who the devil is making that awful stink.
1910		Civil & Milit. Gaz. (Lahore) 17 Mar. 7/3: [T]he poorer classes in India would rather forego food than their chillum of tobacco.

2. (orig. W.I. drugs) a pipe used for smoking marijuana.

1969		R.R. Lingeman Drugs from A to Z (1970) 61: chillum A clay pipe with a short straight stem issuing from the bottom of the bowl.
1983		T. White Catch a Fire 25: The smoking of ganja ‘spliffs’ [...] and herb-packed ‘chillums’ (water pipes).
1995		Francis-Jackson Official Dancehall Dict. 10: Chillum the water pipe used by many for the smoking of ganja, especially by those who smoke it as a part of a religious rite.