gong, n.¹ — Green’s Dictionary of Slang

gong n.¹

[OE gang, the act of walking or going; thus it is, however remotely, an ancestor of the child’s plaint, ‘I’ve got to go’]

the privy.

c.1386

Chaucer Parson’s Tale line 883: Thise fool wommen, that mowe be likned to a commune gong, whereas men purgen hire ordure.

gong farmer (n.)

a cleaner-out of privies, a nightsoil man.

c.1440		Promptuarium Parvulorum 203: Goonge fyrmar [v.r. gonge-fowar], cloacarius.
1515		Cocke Lorelles Bote Bi: Than came a gonge fermourer, Other wyse called a masser scourer [...] Stynkynge gonge fermers.
1596		J. Harington ‘Apologie’ in Metamorphosis of Ajax A2: They swore they were fit for a gong farmer and a chimney sweeper.
2007		T. Sherry Deep Winter 369: Medieval literature. A gong farmer is someone who empties the latrine pit.

gong house (n.)

a privy.

a.1225

Ancrene Riwle 84: Heo beođ þes deofles gongmen, & beođ wiđuten ende in his gong huse.