WORD HISTORIES IV

Average 

The word average came to English through Arabic and French as a maritime term meaning "damage to shipping" - or "damaged goods." It referred to any general expenses over the expected costs of shipping freight. These expenses were usually distributed proportionally among the interested parties in the venture. It is from the notion of the distribution of a sum to a number of persons that the idea of a mathematical average - the arithmetic mean - developed, and from this sense of "mean" or "medium" figure that the senses  of the adjective average,"typical' and "usual," are derived.

Curfew

A curfew was originally a medieval regulation requiring that fires be put out or covered at a certain hour at night. The word derives from the French couvrir (cover) and feu (fire). The rule of curfew was probably instituted as a public safety measure to minimize the risk of a general conflagration. A bell was rung at the prescribed hour, and the word curfew has been extended to denote both the bell and the hour in addition to the regulation.

Mob

Every age has its linguistic fads, and occasionally some of them survive and become part of the standard vocabulary. In the 17th and 18th centuries, the abbreviation of long words or phrases to one or two syllables had a vogue that was much deplored by the self-appointed literary watchdogs of the day. Mob is one such abbreviation that caught on. It is short for mobile, which was used in the early 17th century to mean "the masses." In this usage mobile was itself a shortening of the Latin phrase mobile vulgus, "the excitable populace." The note of contempt originally inherent in the word mob is still with us today.