crust

noun

ˈkrəst 

1

a

: the hardened exterior or surface part of bread

b

: a piece of this or of bread grown dry or hard

2

a

: the pastry shell of a pie : piecrust

b

: the bready layer that forms the foundation of a pizza

3

: a hard or brittle external coat or covering: such as

a

: a hard surface layer (as of soil or snow)

b

: the outer part of a planet, moon, or asteroid composed essentially of crystalline rocks

c

: a deposit built up on the interior surface of a wine bottle during long aging

d

: an encrusting deposit (as of the eye) of dried secretions or exudate

also : scab

4

: gall, nerve

crust verb

crustal

ˈkrə-stᵊl 

adjective

crustless

ˈkrəs(t)-ləs 

adjective

Synonyms

• audaciousness
• audacity
• brashness
• brass
• brassiness
• brazenness
• cheek
• cheekiness
• chutzpah
• chutzpa
• hutzpah
• hutzpa
• effrontery
• face
• gall
• nerve
• nerviness
• pertness
• presumption
• presumptuousness
• sauce
• sauciness
• temerity

Examples of crust in a Sentence

Her children prefer to eat their sandwiches with the crust cut off.

a pie with flaky crust

He likes pizza with thin crust.

Recent Examples on the Web

Quake-prone Japan's four main islands and its outlying islands sit on five major and minor tectonic plates on the Earth's crust—Amur, Okhotsk, Pacific, Philippine Sea, and Okinawa—which are slowly moving, and earthquakes are concentrated along their boundaries. —Jason D. Greenblatt, MSNBC Newsweek, 2 Apr. 2025

The Earth's crust already produces a weak electrical charge which ramps up during a solar storm. —Tom Brown, Space.com, 2 Apr. 2025

The thick crust was hard as ice, and walking on it was very difficult. —Ray Alt, Outdoor Life, 27 Mar. 2025

In those places—generally volcanic hot spots where magma flows at shallow depths in the Earth’s crust and underground water reservoirs—geothermal energy can be a substantial source of power. —Alexander C. Kaufman, The Atlantic, 4 Apr. 2025

Word History

Etymology

Middle English crouste, cruste, borrowed from Anglo-French & Latin; Anglo-French cruste, crouste, going back to Latin crusta "hard coating or surface layer, shell of an arthropod or crustacean, mineral flake, stone slab used in paneling," perhaps, if going back to *krus-to- "something crushed or pounded into a hard layer," from a zero-grade nominal derivative of Indo-European *kreu̯s- "beat, crush, pound," whence also Old English hruse "earth, ground," Old High German roso, rosa "crust, layer of ice" (going back to Germanic *hrusōn-) — more at anacrusis

Note: The hypothetical base *krus-to- is suggested by Michiel de Vaan, Etymological Dictionary of Latin and the Other Italic Languages (Leiden: Brill, 2008), p. 147, though the older handbooks (Walde-Hoffman, Ernout-Meillet) tend to support a connection with Greek krýos "icy cold, frost" and other derivatives, going back to a presumed homonymous *krus- (see cryo-). As de Vaan points out, however, Latin crusta does not mean "ice." The original sense of the Germanic noun *hrusōn- is not certain. Greek krýstallos "ice, rock crystal" is almost certainly unrelated (see crystal entry 1).

First Known Use

14th century, in the meaning defined at sense 1a

Phrases Containing crust

• earn a/one's crust
• the upper crust
• upper crust

Rhymes for crust

• bused
• bust
• cussed
• dust
• fussed
• fust
• gust
• just
• lust
• mussed
• must
• rust

Kids Definition

crust

noun

ˈkrəst 

1

a

: the hardened outside surface of bread

b

: a piece of dry hard bread

2

: the pastry cover of a pie

3

a

: a hard surface layer

a crust of snow

b

: the outer part of the earth

crustal

ˈkrəs-təl 

adjective

Medical Definition

crust

noun

ˈkrəst 

1

: scab sense 2

2

: an encrusting deposit of serum, cellular debris, and bacteria present over or about lesions in some skin diseases (as impetigo or eczema)

crust verb