shell

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Related to shells: Electron shells

shell

(shel),
An outer covering.

shell

Etymology: AS, scell
1 a hard outer protective covering that encloses material.
2 a principal energy level occupied by an electron in an atom.

shell

(shel)
An outer covering.

shell

any hard outer covering, such as the carapace of turtles and tortoises, the exoskeleton of crustaceans, the calcareous plates of echinoderms, the outermost membranes of an egg, the skeleton of Foraminifera or the mantle secretions of molluscs.

impression, eye

A negative form or replica of the anterior part of the eye. A substance with rapid gelling properties is held in contact with the eye until gelled. This impression (or mould) is then used in the preparation of a positive model called a cast (or casting) of the anterior part of the eye: it is made by filling the impression with a material containing a plaster of Paris base which hardens to artificial stone. Using this cast a shell of a scleral contact lens is produced with optimum shape of the back surface. Syn. impression; impression moulding; mould; ocular impression.
References in classic literature ?
Jerry had just gained the doorway when the shell exploded.
The evidence of rarity preceding extinction, is more striking in the successive tertiary strata, as remarked by several able observers; it has often been found that a shell very common in a tertiary stratum is now most rare, and has even long been thought extinct.
The light disclosed the frightful injury which a fragment of the shell had inflicted on the Englishwoman's head.
He turned from the bed, and illustrated his disgust by spitting on the fragments of the exploded shell.
It comes o' sittin' on th' grass under a tree wi' Dickon an' wi' Captain an' Soot an' Nut an' Shell.
It seemed as if Colin could never hear enough of Dickon and Captain and Soot and Nut and Shell and the pony whose name was Jump.
3 : to shoot shells at or upon <They shelled the enemy troops.
ABSTRACT Hermit crabs select shells based on size, weight, species of gastropod, and shell condition.
The first step in any Fourth of July show is to decide what types of shells, or fireworks, will wow the crowd.
In the current study, the researchers studied the lead isotopic compositions of cocoa beans and shells from six farms in Nigeria's top three producing states to determine if soil or farm sources might be the cause of lead contamination.
Here is a stunt for you using three shells and three smooth, ocean stones.
Researchers have developed a new way to use mussel shells to diagnose a sick environment.