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bronchitis

(Encyclopedia)bronchitis brŏnkīˈtĭs [key], inflammation of the mucous membrane of the bronchial tubes. It can be caused by viral or bacterial infections or by allergic reactions to irritants such as tobacco smo...

age grade and age set

(Encyclopedia)age grade and age set, differentiation of social role based on age, commonly found in small-scale societies of North America and East Africa. Age sets are a type of sodality (nonresidential groups tha...

pneumothorax

(Encyclopedia)pneumothorax no͞omōthôrˈăks [key], collapse of a lung with escape of air into the pleural cavity between the lung and the chest wall. The cause may be traumatic (e.g., gunshot or stab wound), spo...

vomiting

(Encyclopedia)vomiting, ejection of food and other matter from the stomach through the mouth, often preceded by nausea. The process is initiated by stimulation of the vomiting center of the brain by nerve impulses ...

weather vane

(Encyclopedia)weather vane or wind vane, instrument used to indicate wind direction. It consists of an asymmetrically shaped object, e.g., an arrow or a rooster, mounted at its center of gravity so it can move free...

airmail

(Encyclopedia)airmail, transport of mail by airplanes. Demonstration flights that showed the feasibility of carrying mail by air were made in Great Britain and in the United States in 1911. In the United States, af...

black widow

(Encyclopedia)black widow, poisonous spider of the genus Latrodectus, found throughout North and South America and common in the SW United States. The name derives from the fact that the female, like those of many ...

borzoi

(Encyclopedia)borzoi bôrˈzoi [key], breed of tall, swift hound developed in Russia in the early 17th cent., also called Russian wolfhound. It stands from 26 to 31 in. (66–81.2 cm) high at the shoulder and weigh...

Minot, Laurence

(Encyclopedia)Minot, Laurence, fl. 1333–52, English poet. He was the author of fervently patriotic war poems about Halidon Hill, the siege of Calais, and other battles. Probably a Yorkshireman, he may have been a...

pollination

(Encyclopedia)pollination, transfer of pollen from the male reproductive organ (stamen or staminate cone) to the female reproductive organ (pistil or pistillate cone) of the same or of another flower or cone. Polli...