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trachoma

(Encyclopedia)trachoma trəkōˈmə [key], infection of the mucous membrane of the eyelids caused by the bacterium Chlamydia trachomatis. Trachoma affects at least 86 million people worldwide. An estimated 1.9 mill...

permafrost

(Encyclopedia)permafrost, permanently frozen soil, subsoil, or other deposit, characteristic of arctic and some subarctic regions; similar conditions are also found at very high altitudes in mountain ranges. In 196...

Caillaux, Joseph

(Encyclopedia)Caillaux, Joseph zhôzĕfˈ kāyōˈ [key], 1863–1944, French statesman. Son of a former cabinet minister, he entered the French civil service as inspector of finance. He later became finance minist...

Yoruba

(Encyclopedia)Yoruba yōˈro͞obä [key], people of SW Nigeria and Benin, numbering about 20 million. Today many of the large cities in Nigeria (including Lagos, Ibadan, and Abeokuta) are in Yorubaland. The old Yor...

Ainu

(Encyclopedia)Ainu īˈno͞o [key], aborigines of Japan who may be descended from a Caucasoid people who once lived in N Asia. More powerful invaders from the Asian mainland gradually forced the Ainu to retreat to ...

Verwoerd, Hendrik Frensch

(Encyclopedia)Verwoerd, Hendrik Frensch hĕnˈdrək frĕnsh fərvo͞ortˈ [key], 1901–66, South African political leader, b. Holland. He was taken as an infant to South Africa when his parents emigrated as missio...

insecticides

(Encyclopedia)insecticides, chemical, biological, or other agents used to destroy insect pests; the term commonly refers to chemical agents only. The liabilities of chemical insecticides have encouraged interest ...

syphilis

(Encyclopedia)syphilis sĭfˈəlĭs [key], contagious sexually transmitted disease caused by the spirochete Treponema pallidum (described by Fritz Schaudinn and Erich Hoffmann in 1905). Syphilis was not widely reco...

sulfuric acid

(Encyclopedia)sulfuric acid, chemical compound, H2SO4, colorless, odorless, extremely corrosive, oily liquid. It is sometimes called oil of vitriol. Although sulfuric acid is now one of the most widely used c...

harvester

(Encyclopedia)harvester, farm machine that mechanically harvests a crop. Small-grain harvesting has been mechanized to a certain extent since early times. In the modern period the first harvester to gain general ac...