A stevedore, dockworker, docker, dock laborer, wharfie, wharf rat, lumper, and/or longshoreman is a waterfront manual laborer who is involved in loading and unloading ships. The word stevedore originated in Portugal or Spain, and entered the English language through its use by sailors. It started as a phonetic spelling of estivador (Portuguese) or estibador (Catalan and Spanish), meaning a man who loads ships and stows cargo, which was the original meaning of stevedore (though there is a secondary meaning of "a man who stuffs" in Spanish); compare Latin stipare meaning to stuff, as in to fill with stuffing. In the United Kingdom, men who load and unload ships are usually called dockers, in Australia dockers or wharfies, while in the United States and Canada the term longshoreman, derived from man-along-the-shore, is used. Before extensive use of container ships and shore-based handling machinery in the United States, longshoremen referred exclusively to the dockworkers, while stevedores, in a separate trade union, worked on the ships, operating ships cranes and moving cargo. In Canada, the term stevedore has also been used, for example, in the name of the Western Stevedoring Company, Ltd., based in Vancouver, B.C., in the 1950s. Loading and unloading ships requires knowledge of the operation of loading equipment, the proper techniques for lifting and stowing cargo, and correct handling of hazardous materials. In addition, workers must be physically strong and be able to follow orders attentively.