Noun

(centuries)

A period of 100 consecutive years; often specifically'' a numbered period with conventional start and end dates, e.g., the ''twentieth century'', which stretches from (''strictly'') 1901 through 2000, or (''informally'') 1900 through 1999. The ''first century AD was from 1 to 100; a yearhundred.

* {{quote-book, year=1963, author=(Margery Allingham)

, title=(The China Governess), chapter=Foreword citation , passage=He stood transfixed before the unaccustomed view of London at night time, a vast panorama which reminded him […] of some wood engravings far off and magical, in a printshop in his childhood. They dated from the previous century and were coarsely printed on tinted paper, with tinsel outlining the design.}}

* {{quote-magazine, date=2013-07-20, volume=408, issue=8845, magazine=(The Economist)

, title= The attack of the MOOCs , passage=Since the launch early last year of […] two Silicon Valley start-ups offering free education through MOOCs, massive open online courses, the ivory towers of academia have been shaken to their foundations. University brands built in some cases over centuries have been forced to contemplate the possibility that information technology will rapidly make their existing business model obsolete.}}

A unit in ancient Roman army, originally of 100 army soldiers as part of a cohort, later of more varied sizes (but typically containing 60 to 70 or 80) soldiers or other men (guards, police, firemen), commanded by a centurion.

A political division of ancient Rome, meeting in the Centuriate Assembly.

(archaic)  A hundred things; a hundred.

*, II.4.2.i:

'tis the subject of whole books: I might cite a century of authors pro'' and ''con .

(cricket)  A hundred runs scored either by a single player in one innings, or by two players in a partnership.

(cycling)  A ride 100 kilometres in length.

(US, informal)  A banknote in the denomination of one hundred dollars.

Noun

(en noun)

A hard external covering of an animal.

# The calcareous or chitinous external covering of mollusks, crustaceans, and some other invertebrates.

In some mollusks, as the cuttlefish, the shell is concealed by the animal's outer mantle and is considered internal.

Genuine mother of pearl buttons are made from sea shells .

# (by extension) Any mollusk having such a covering.

# (entomology) The exoskeleton or wing covers of certain insects.

# The conjoined scutes that comprise the "shell" (carapace) of a tortoise or turtle.

# The overlapping hard plates comprising the armor covering the armadillo's body.

The hard calcareous covering of a bird egg.

The hard external covering of various plant seed forms.

# The covering, or outside part, of a nut.

The black walnut and the hickory nut, both of the same ''Genus as the pecan, have much thicker and harder shells than the pecan.

# A pod containing the seeds of certain plants, such as the legume Phaseolus vulgaris .

# (in the plural) Husks of cacao seeds, a decoction of which is sometimes used as a substitute or adulterant for cocoa and its products such as chocolate.

The accreted mineral formed around a hollow geode.

The casing of a self-contained single-unit artillery projectile.

A hollow usually spherical or cylindrical projectile fired from a siege mortar or a smoothbore cannon. It contains an explosive substance designed to be ignited by a fuse or by percussion at the target site so that it will burst and scattered at high velocity its contents and fragments. Formerly called a bomb.

The cartridge of a breechloading firearm; a load; a bullet; a round.

Any slight hollow structure; a framework, or exterior structure, regarded as not complete or filled in, as the shell of a house.

A garment, usually worn by women, such as a shirt, blouse, or top, with short sleeves or no sleeves, that often fastens in the rear.

A coarse or flimsy coffin; a thin interior coffin enclosed within a more substantial one.

(Knight)

(music) A string instrument, as a lyre, whose acoustical chamber is formed like a shell.

The first lyre may have been made by drawing strings over the underside of a tortoise shell.

* Dryden

when Jubal struck the chorded shell

(music) The body of a drum; the often wooden, often cylindrical acoustic chamber, with or without rims added for tuning and for attaching the drum head.

An engraved copper roller used in print works.

(nautical) The watertight outer covering of the hull of a vessel, often made with planking or metal plating.

(nautical, rigging) The outer frame or case of a block within which the sheaves revolve.

(nautical) A light boat the frame of which is covered with thin wood, impermeable fabric, or water-proofed paper; a racing shell or dragon boat.

(computing) An operating system software user interface, whose primary purpose is to launch other programs and control their interactions; the user's command interpreter.

The name shell originates from it being viewed as an outer layer of interface between the user and the internals of the operating system.

The name "Bash" is an acronym which stands for "Bourne-again shell", itself a pun on the name of the "Bourne shell", an earlier Unix shell designed by Stephen Bourne, and the Christian concept of being "born again".

(chemistry) A set of atomic orbitals that have the same principal quantum number.

An emaciated person.

He's lost so much weight from illness; he's a shell of his former self.

A psychological barrier to social interaction.

Even after months of therapy he's still in his shell .

(business) A legal entity that has no operations.

A shell corporation was formed to acquire the old factory.