Columbia Encyclopedia World Factbook American Heritage Coll. Physical or mental effort or activity directed toward the production or accomplishment of something. A trade, profession, or other means of livelihood.
Erosion is the work of wind, water, and time.
A fortified structure, such as a trench or fortress. A piece of such textile art. A factory, plant, or similar building or complex of buildings where a specific type of business or industry is carried on. The transfer of energy from one physical system to another, especially the transfer of energy to a body by the application of a force that moves the body in the direction of the force. It is calculated as the product of the force and the distance through which the body moves and is expressed in joules, ergs, and foot-pounds.