crust

UK: /ˈkrʌst/ US: /krʌst/ ,(krust)

WordReference Random House Learner's Dictionary of American English © 2026

crust /krʌst/   n. [countable]

1. Food the brown, hard outer surface of a loaf of bread.
2. Food a slice of bread from the end of the loaf.
3. Food the pastry containing the filling of a pie or other dish.
4. • any hard outer covering or coating, as of ice or snow.
   • [usually singular] the outer layer of the earth:
     The earth's crust is about 22 mi. (35 km) deep under the continents and 6 mi. (10 km) deep under the oceans.

v. [~ + object]

5. to cover with a crust:
   The road was crusted with snow and ice.

crust•al, adj.: 

the earth's crustal plates.

WordReference Random House Unabridged Dictionary of American English © 2026

crust  (krust), n. 

1. Food the brown, hard outer portion or surface of a loaf or slice of bread (distinguished from crumb).
2. Food a slice of bread from the end of a loaf, consisting chiefly of this.
3. Food 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. Geology 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), core ¹ (def. 10).
7. a scab or eschar.
8. Slang Terms unabashed self-assertiveness;
   nerve;
   gall:
   He had a lot of crust going to the party without an invitation.
9. Wine deposit from wine, as it ripens during aging, on the interior of bottles, consisting of tartar and coloring matter.
10. Invertebrates the hard outer shell or covering of an animal.
11. British Terms [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.

• Latin crusta hard coating, crust
• Anglo-French, Old French cruste, croste
• Middle English 1275–1325

crust′less, adj. 

Collins Concise English Dictionary © HarperCollins Publishers::

crust / krʌst/ noun

1. the hard outer part of bread
2. a piece of bread consisting mainly of this
3. the baked shell of a pie, tart, etc
4. any hard or stiff outer covering or surface: a crust of ice
5. 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 discontinuity
   See also sial, sima
6. the dry covering of a skin sore or lesion; scab
7. impertinence
8. a living (esp in the phrase earn a crust)

verb

1. to cover with or acquire a crust
2. to form or be formed into a crust

Etymology: 14th Century: from Latin crūsta hard surface, rind, shell