—crustless, adj./krust/, n.1. the brown, hard outer portion or surface of a loaf or slice of bread (distinguished from crumb).2. a slice of bread from the end of a loaf, consisting chiefly of this.3. the pastry covering the outside of a pie or other dish.4. a piece of stale bread.5. any more or less hard external covering or coating: a crust of snow.6. Geol. the outer layer of the earth, about 22 mi. (35 km) deep under the continents and 6 mi. (10 km) deep under the oceans. Cf. mantle (def. 3), core1 (def. 10).7. a scab or eschar.8. Slang. unabashed self-assertiveness; nerve; gall: He had a lot of crust going to the party without an invitation.9. deposit from wine, as it ripens during aging, on the interior of bottles, consisting of tartar and coloring matter.10. the hard outer shell or covering of an animal.11. Australian Slang. a living or livelihood: What do you do for a crust?v.t.12. to cover with or as with a crust; encrust.13. to form (something) into a crust.v.i.14. to form or contract a crust.15. to form into a crust.[1275-1325; ME < AF, OF cruste, croste < L crusta hard coating, crust]
* * *Outermost solid part of the Earth, essentially composed of a range of igneous and metamorphic rock types.In continental regions, the crust is made up chiefly of granitic rock, whereas the composition of the ocean floor corresponds mainly to that of basalt and gabbro. On average, the crust extends 22 mi (35 km) downward from the surface to the underlying mantle, from which it is separated by the Mohorovičić discontinuity (the Moho). The crust and top layer of the mantle together form the lithosphere.
* * *the outermost solid part of the Earth (q.v.), essentially composed of rocky materials.
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