noun
inner core (of Earth)
Geological term for the solid innermost part of the Earth, contrasted with 外核 (outer core).
See also: 外核
地球の内核は固体の鉄とニッケルでできていると考えられている。
The Earth's inner core is thought to be made of solid iron and nickel.
内核と外核の境界は約5100kmの深さにある。
The boundary between the inner core and outer core is at a depth of about 5100 km.