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conch

(Encyclopedia)conch kŏngk, kŏnch, kôngk [key], common name for certain marine gastropod mollusks having a heavy, spiral shell, the whorls of which overlap each other. In conchs the characteristic gastropod foot ...

gastropod

(Encyclopedia)CE5 Internal anatomy of a snail, Helix aspersa, representative mollusk of the class Gastropoda gastropod, member of the class Gastropoda, the largest and most successful class of mollusks (phylum ...

tracery

(Encyclopedia)CE5 Types of tracery tracery, bands or bars of stone, wood, or other material, either subdividing an opening or standing in relief against a wall and forming an ornamental pattern of solid members...

cluster munitions

(Encyclopedia)cluster munitions or cluster bombs, air-dropped or ground-launched weapons that open in mid-air and scatter dozens, hundreds, or thousands of smaller submunitions (or bomblets) over a wide area. Such ...

metalwork

(Encyclopedia)metalwork. Copper, gold, and silver were probably fashioned into ornaments and amulets as early as the Neolithic period. Goldwork and silverwork have since employed the talents of leading artisans and...

ozone

(Encyclopedia)ozone ōˈzōn [key], an allotropic form of the chemical element oxygen (see allotropy). Pure ozone is an unstable, faintly bluish gas with a characteristic fresh, penetrating odor. The gas has a dens...

tin

(Encyclopedia)tin, metallic chemical element; symbol Sn [Lat. stannum]; at. no. 50; at. wt. 118.710; m.p. 231.9681℃; b.p. 2,270℃; sp. gr. 5.75 (gray), 7.3 (white); valence +2 or +4. Tin exhibits allotropy; abov...

radiometer

(Encyclopedia)radiometer rāˌdēŏmˈətər [key], instrument for detection or measurement of electromagnetic radiation; the term is applied in particular to devices used to measure infrared radiation. One of the ...

mask

(Encyclopedia)mask, cover or partial cover for the face or head used as a disguise or protection. Masks have been worn from time immemorial throughout the world. They are used by primitive peoples chiefly to impers...

titanium

(Encyclopedia)titanium tītāˈnēəm, tĭ– [key] [from Titan], metallic chemical element; symbol Ti; at. no. 22; at. wt. 47.867; m.p. 1,675℃; b.p. 3,260℃; sp. gr. 4.54 at 20℃; valence +2, +3, or +4. Titani...