Definition of "fatberg"

Months ago a tunnel was clogged with a fatberg. It took a team of workers a month to move it.

2009, Carlos J. Cortes, “The Prisoner”, in The Prisoner, New York, N.Y.: Spectra; Ballantine Books, page 162

Bleeding big fatberg up there. About half a ton's worth. [...] Gorman feels an involuntary shudder travel down his spine and agitate his stomach. He's seen those fatbergs on the training videos; huge accumulated walls of solidified grease and food and tissue and excrement, the churned result of everyday debris tipped down the domestic sinks and bathtubs and toilets of London.

2013, Russ Litten, Swear Down‎, London: Tindal Street Press

Then I worked in the sewers of Manchester – a six month stint of that, jabbing pressure-water-poles at fatbergs, tonnes of used kebab grease and congealed sump oil, woven together with thousands of used wet wipes.

2014, Adam Roberts, “Anne”, in Bête, London: Gollancz

A 250-metre long fatberg weighing 130 tonnes which was blocking an east London sewer has been cleared after a nine-week "battle". The solid mass of congealed fat, wet wipes, nappies, oil and condoms was found in the Victorian-era tunnel in Whitechapel in September. Thames Water said it had taken longer to clear than expected because of the damage it caused to the sewer.

2017 November 3, “‘Victory declared’ over 130 tonne Whitechapel fatberg”, in BBC News‎, archived from the original on 18 March 2018

Thames Water has become the latest object lesson in the predictable and predicted folly of privatised monopolies, aided by a regulator that’s an even bigger wet wipe than the fatbergs bunging up the sewers.

2023 June 30, Marina Hyde, “The tide is coming in fast on Rishi Sunak – and it’s full of sewage”, in The Guardian‎