crust
KRUST
/krʌst/
The outer hard layer of the Earth or another planetary body.
In geology, refers to the solid, thin outer shell of Earth sitting atop the mantle.
The story behind the word. Directly from Latin 'crusta', meaning rind, shell, or hard outer surface. Geologists adapted the term to describe the hard outer skin of rock encircling the liquid and semi-solid inner zones of Earth.
Word relationships
- shell: Shell is a general protective outer coating, while crust specifically implies a hard outer layer over a softer core.
- surface layer: Surface layer is descriptive, whereas crust is the formal geological term for Earth's outermost rock layer.
- core: Core refers to the innermost center of the Earth, while crust is the outermost skin.
Commonly confused with
- mantle: The mantle lies directly beneath Earth's crust and makes up the bulk of Earth's volume.
Word family
- crustal (adjective): Relating to a crust, especially Earth's crust
- encrust (verb): To cover with a hard surface crust
Collocations
- Earth's crust
- continental crust
- oceanic crust
- crustal movement
Idioms & expressions
- upper crust
Example sentences
- "The oceanic crust is noticeably thinner and denser than the thick continental crust." Earth science
- "Tectonic movements cause deep fractures and shifting landmasses across the Earth's crust." Physical geography
Memory hook
Just like bread crust is the outer skin, Earth's crust is the rock skin. Outer rock shell.
When not to use
Do not confuse with the deep interior layers like the mantle or core.
Fun facts
- The Earth's crust accounts for less than 1% of the planet's total volume.
Explore more words
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