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Hadal

/ˈheɪdəl/adjective

Belonging to the deepest ocean zone, below about 6,000 metres, found only in trenches.

The Greek roots

Ἅιδης
Háidēs
Hades, the underworld

Literally: of the underworld

Follow a root:Ἅιδης2 words

The story of the word

Coined by oceanographers in the 1950s after the abyssal zone below the bathyal, since the naming had already run out of Greek depths. Hades named the god before it named the place, and the region was often called "the house of Hades" to keep the two apart. Trieste reached the hadal floor of the Mariana Trench in 1960 and found a flatfish, or thought it did.

How it travelled
Ancient Greek → scientific coinage → English
First recorded
20th century

Same family

Hadesabyssalbathyal

In a sentence

Hadal snailfish have been filmed at eight kilometres down.

Only about forty-five trenches worldwide reach hadal depths.

Built on the same root

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