Columbia Encyclopedia

(Encyclopedia) swim bladder, large, thin-walled sac in some fishes that may function in several ways, e.g., as a buoyant float, a sound producer and receptor, and a respiratory organ. The swim bladder, or air bladde...

(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 ...

(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...

(Encyclopedia) probate prōˈbāt [key], in law, the certification by a court that a will is valid. Probate, which is governed by various statutes in the several states of the United States, is required before the w...

(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...

(Encyclopedia) speech defect, any condition that interferes with the mental formation of words or their physical production. Speech defects in children generally become apparent in the early school years. Speech pro...

(Encyclopedia) sports medicine, branch of medicine concerned with physical fitness and with the treatment and prevention of injuries and other disorders related to sports. Knee, leg, back, and shoulder injuries; sti...

(Encyclopedia) squash tennis, game played on a four-walled court, similar in dimensions to the court on which squash racquets is played. The two games, however, differ in equipment, rules, and play. The squash tenni...

(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...

(Encyclopedia) electric shock, effect of the passage of a current of electricity through the body. Fatality may result from shocks of from 1 to 2 amperes and 500 to 1,000 volts. However, the effect of electric shock...