Where does “fatberg” come from?

fatberg (English) comes from English Berg, from English iceberg, from Dutch ijsberg, from Dutch ĳs, from Middle Dutch ĳs, from Old Dutch īs, from Proto-West Germanic īs, from Proto-Germanic īsą — ice, frost.

fatberg (English): A large accumulation of fat and discarded...

Definitions

A large accumulation of fat and discarded...

Ancestry of “fatberg”, step by step

fatberg traces back through two separate lines of ancestry.

via English Berg

Step	Language	Word	Meaning
1	English	Berg	A place name, notably of
2	English	iceberg	The seaward end of a glacier; A huge mass of...
3	Dutch	ijsberg	iceberg
4	Dutch	ĳs	ice frozen liquid, notably water
5	Middle Dutch	ĳs	ice
6	Old Dutch	īs	—
7	Proto-West Germanic	īs	ice
8	Proto-Germanic	īsą	ice
9	Proto-Indo-European	h₁eyH-	ice, frost

via English fat

Step	Language	Word	Meaning
1	English	fat	Carrying more fat than usual on one's body;...
2	French	fat	conceited
3	Old Occitan	fat	—
4	Latin	fatuus	foolish, silly, simple; stupid; insipid,...
5	Latin	fātus	spoken, said, told, foretold, related, predicted; having or had spoken, etc
6	Latin	for	"defective"; I speak, talk, say
7	Proto-Italic	fāōr	speak
8	Proto-Indo-European	bʰéh₂ti	to speak, to be talking

Every word from Proto-Indo-European h₁eyH- →Every word from Proto-Germanic īsą →Every word from Proto-West Germanic īs →