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sand

(Encyclopedia)sand, rock material occurring in the form of loose, rounded or angular grains, varying in size from .06 mm to 2 mm in diameter, the particles being smaller than those of gravel and larger than those o...

Ordovician period

(Encyclopedia)Ordovician period ôrdəvĭshˈən [key] [from the Ordovices, ancient tribe of N Wales], second period of the Paleozoic era of geologic time (see Geologic Timescale, tablegeologic timescale, table) fr...

Aden

(Encyclopedia)Aden äˈdən, āˈdən [key], city, SW Yemen, on the Gulf of Aden near the southern entrance to the Red Sea. It is the chief port of Yemen. Aden consists of two peninsula...

La Salle, Robert Cavelier, sieur de

(Encyclopedia)La Salle, Robert Cavelier, sieur de rōbĕrˈ kävəlyāˈ syör də lä sälˈ [key], 1643–87, French explorer in North America, one of the most celebrated explorers and builders of New France. He ...

Penn, William, founder of Pennsylvania

(Encyclopedia)Penn, William, 1644–1718, English Quaker, founder of Pennsylvania, b. London, England; son of Sir William Penn. Penn became involved in the affairs of the American colonies when in 1675 he was ap...

clam

(Encyclopedia)clam, common name for certain bivalve mollusks, especially for marine species that live buried in mud or sand and have valves (the two pieces of the shell) of equal size. The oval valves, which cover ...

Baptists

(Encyclopedia)Baptists, denomination of Protestant Christians holding a distinctive belief with regard to the ordinance of baptism. Since 1644 the name has been applied to those who maintain that baptism should be ...

Triassic period

(Encyclopedia)Triassic period trīăsˈĭk [key], first period of the Mesozoic era of geologic time (see Geologic Timescale, tablegeologic timescale, table) from 205 to 250 million years ago. Throughout the Triassi...

Cretaceous period

(Encyclopedia)Cretaceous period krĭtāˈshəs [key], third and last period of the Mesozoic era of geologic time (see Geologic Timescale, tablegeologic timescale, table), lasting from approximately 144 to 65 millio...

ass

(Encyclopedia)ass, hoofed, herbivorous mammal of the genus Equus, closely related to the horse. It is distinguished from the horse by its small size, large head, long ears, and small hooves. There are three living ...