fatberg
n. A massive, hardened agglomeration of fatty substances, particularly one found in a sewer and caused by homeowners and businesses pouring fats down drains.
Etymology
Examples
2017
First, someone might pour molten turkey fat down a drain. A few blocks away, someone else might flush a wet wipe down a toilet. When the two meet in a dank sewer pipe, a baby fatberg is born.
—Erika Engelhaupt, “Huge Blobs of Fat and Trash Are Filling the World’s Sewers,” National Geographic, August 16, 2017
2016
Enormous clusters of wet wipes are creating "fatbergs" that are clogging up sewer pipes across NSW, including a one-tonne cluster that blew out a pumping station near Lake Macquarie.
—Gabriel Wingate-Pearse & Glen Humphries, “Fatbergs: One tonne balls of wet wipes and fat block sewers,” The Sydney Morning Herald, February 25, 2016
2015
Fatbergs—formed when fat clumps together with other household waste—are becoming an increasing problem for London’s sewers.
—Rebecca Ratcliffe, “10-tonne fatberg removed from west London sewer,” The Guardian, April 21, 2015
2009 (earliest)
—“Cleaning a Fatberg - Hydro Cleansing,” YouTube, September 15, 2009