- the brown, hard outer portion or surface of a loaf or slice of bread (distinguished from crumb).
- a slice of bread from the end of a loaf, consisting chiefly of this.
- the pastry covering the outside of a pie or other dish.
- a piece of stale bread.
- any more or less hard external covering or coating: a crust of snow.
- Geology. the outer layer of the earth, about 22 miles (35 km) deep under the continents (continental crust)and 6 miles (10 km) deep under the oceans (oceanic crust).Compare mantle(def 3), core1(def 10).
- a scab or eschar.
- Slang. unabashed self-assertiveness; nerve; gall: He had a lot of crust going to the party without an invitation.
- deposit from wine, as it ripens during aging, on the interior of bottles, consisting of tartar and coloring matter.
- the hard outer shell or covering of an animal.
- Australian Slang. a living or livelihood: What do you do for a crust?
- to cover with or as with a crust; encrust.
- to form (something) into a crust.
- to form or contract a crust.
- to form into a crust.
Origin of crust
- the hard outer part of bread
- a piece of bread consisting mainly of this
- the baked shell of a pie, tart, etc
- any hard or stiff outer covering or surfacea crust of ice
- the solid outer shell of the earth, with an average thickness of 30–35 km in continental regions and 5 km beneath the oceans, forming the upper part of the lithosphere and lying immediately above the mantle, from which it is separated by the Mohorovičić discontinuitySee also sial, sima
- the dry covering of a skin sore or lesion; scab
- a layer of acid potassium tartrate deposited by some wine, esp port, on the inside of the bottle
- the hard outer layer of such organisms as lichens and crustaceans
- slang impertinence
- British, Australian and NZ slang a living (esp in the phrase earn a crust)
- to cover with or acquire a crust
- to form or be formed into a crust
Word Origin and History for oceanic crust
early 14c., "hard outer part of bread," from Old French crouste (13c., Modern French croûte) and directly from Latin crusta "rind, crust, shell, bark," from PIE *krus-to- "that which has been hardened," from root *kreus- "to begin to freeze, form a crust" (cf. Sanskrit krud- "make hard, thicken;" Avestan xruzdra- "hard;" Greek krystallos "ice, crystal," kryos "icy cold, frost;" Lettish kruwesis "frozen mud;" Old High German hrosa "ice, crust;" Old English hruse "earth;" Old Norse hroðr "scurf"). Meaning "outer shell of the earth" is from 1550s.
late 14c.; see crust (n.). Related: Crusted; crusting.
- A hard, crisp covering or surface.
- An outer layer or coating formed by the drying of a bodily exudate such as pus or blood; a scab.
- To cover with, become covered with, or harden into a crust.
- See under crust.
- The solid, outermost layer of the Earth, lying above the mantle.♦ The crust that includes continents is called continental crust and is about 35.4 to 70 km (22 to 43.4 mi) thick. It consists mostly of rocks, such as granites and granodiorites, that are rich in silica and aluminum, with minor amounts of iron, magnesium, calcium, sodium, and potassium.♦ The crust that includes ocean floors is called oceanic crust and is about 4.8 to 9.7 km (3 to 6 mi) thick. It has a similar composition to that of continental crust, but has higher concentrations of iron, magnesium, and calcium and is denser than continental crust. The predominant type of rock in oceanic crust is basalt.
Idioms and Phrases with oceanic crust
see upper crust.