Acanthocephala :: Acanthocephala (n. pl.) A group of intestinal worms, having the proboscis armed with recurved spines..
Acephala :: Acephala (n. pl.) That division of the Mollusca which includes the bivalve shells, like the clams and oysters; -- so called because they have no evident head. Formerly the group included the Tunicata, Brachiopoda, and sometimes the Bryozoa. See Mollusca..
Alabama Period :: Alabama period () A period in the American eocene, the lowest in the tertiary age except the lignitic..
Alabaster :: Alabaster (n.) A compact variety or sulphate of lime, or gypsum, of fine texture, and usually white and translucent, but sometimes yellow, red, or gray. It is carved into vases, mantel ornaments, etc..
Alabaster :: Alabaster (n.) A hard, compact variety of carbonate of lime, somewhat translucent, or of banded shades of color; stalagmite. The name is used in this sense by Pliny. It is sometimes distinguished as oriental alabaster..
Alabaster :: Alabaster (n.) A box or vessel for holding odoriferous ointments, etc.; -- so called from the stone of which it was originally made..
Alacrity :: Alacrity (n.) A cheerful readiness, willingness, or promptitude; joyous activity; briskness; sprightliness; as, the soldiers advanced with alacrity to meet the enemy..
Aladinist :: Aladinist (n.) One of a sect of freethinkers among the Mohammedans.